Answer:
0.0025moles
Explanation:
Molarity of a solution (M) = number of moles (n) ÷ volume (V)
According to this question, to make 250 mL of a 0.01 M solution of CaCl, the following number of moles is needed:
Volume = 250mL = 250/1000 = 0.250Litres.
Using; molarity = n/V
0.01 = n/0.250
n = 0.0025
n = 2.5 × 10^-3 moles.
[URGENT!] - Acids and Bases
a) What is the pH of a solution in which 25.0 ml of a 0.400 M solution of HCl is added to 75.0 ml of a 0.500 M solution of ammonium hydroxide?
b) If 0.050 moles of KOH were added to the buffer solution, what would be the resulting pH?
c) Explain what chemical reaction(s) happen as KOH is added to the buffer solution.
Answer:
b) answer. NaOH is a strong base, meaning it will dissociate basically completely in solution to form
N
a
+
and
O
H
−
ions in solution.
One mole of
O
H
−
ions is created for every mole of NaOH that is dissolved. If it's a .05 M solution of NaOH, then it can also be interpreted to be a .05M solution of
OH−.pOH
(The pH scale for bases) can be found by taking the negative logarithm of OH− concentration.
pOH = −log
[05M] = 1.3.
However, we are trying to find
pH
, so we must use the formula pOH+pH
=14 .Now that we know pOH
=1.3pH=14−1.3=12.7
.
How can you prevent food storage areas from cross contamination from bacteria and other hazards?
What is cross contamination?
The physical transfer of dangerous microorganisms from one person, object, or location to another is known as cross-contamination. One of the most important steps in preventing foodborne illness is preventing cross-contamination.
Cover all raw ingredients, especially meat, and keep them apart from prepared foods.Use a dish with a lid if you want to avoid spills.Keep raw meat, poultry, fish, and shellfish covered in your refrigerator's bottom shelf.For raw and cooked food, use various utensils, plates, and cutting boards.To learn more about cross contamination from the given link.
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a student trying to prepare aspirin begins with 2.52 g of salicylic acid and excess acetic anhydride. what is the students theoretical yield of aspirin? show your work g
The theoretical yield of aspirin that a student can prepare from 2.52 g of salicylic acid and excess acetic anhydride is 3.28 g.
The theoretical yield of aspirin that a student can prepare from 2.52 g of salicylic acid and excess acetic anhydride can be calculated using the following steps:
Calculate the moles of salicylic acid (SA):
Moles of SA = 2.52 g/138.12 g/mol = 0.01826 mol
Calculate the moles of acetic anhydride (AA):
Moles of AA = 0.01826 mol/1 mol = 0.01826 mol
Calculate the theoretical yield of aspirin (ASA):
Moles of ASA = 0.01826 mol x 1 mol/1 mol = 0.01826 mol
Convert the moles of ASA to grams:
Grams of ASA = 0.01826 mol x 180.15 g/mol = 3.28 g
Therefore, the theoretical yield of aspirin that a student can prepare from 2.52 g of salicylic acid and excess acetic anhydride is 3.28 g.
If the student obtains 1.71 g of aspirin, then the percent yield can be calculated using the following equation:
Percent Yield = (Actual yield/Theoretical yield) x 100
Percent Yield = (1.71 g/3.28 g) x 100 = 52.2%
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Complete question is attached below.
How do you tell if pewter has lead in it?
The best approach to determine whether a piece of pewter contains lead is to use a lead test kit from the hardware store. Here, a section of metal is swabbed with test chemicals to see if the color changes. Lead is typically indicated by pink or red kits.
Lead content in antique pewter?30 percent lead and 70 percent tin were the main components of ancient pewter. When exposed to acidic foods, this type of pewter, often known as black metal, quickly leached away its lead.
What caused the removal of lead from pewter?It's vital to remember that early pewter contained a lot of lead. Due to lead's hazardous nature, everyday or frequent use caused the chemical to leak out of the plate and spoon.
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complete the calvin cycle by filling in the missing molecules.
The Calvin cycle by filling in the missing molecules Ribulose 1,5-bisphosphate (5C) (RuBP)
The Calvin cycle, also known as the light-independent reactions, bio synthetic phase, dark reactions, or photosynthetic carbon reduction (PCR) cycle[1] of photosynthesis, is a sequence of chemical processes that transform carbon dioxide and hydrogen-carrier molecules into glucose. In all photosynthetic eukaryotes as well as many photosynthetic bacteria, the Calvin cycle is present. The stroma, the area of a chloroplast that is fluid-filled and not covered by thylakoid membranes, is where these reactions take place in plants. These reactions take the byproducts of light-dependent reactions (ATP and NADPH), and put them through additional chemical pathways. To create sugars that the plant can utilise, the Calvin cycle combines the reducing power of NADPH and the chemical energy of ATP. These substrates are utilised in a sequence of reduction-oxidation processes that result in the production of sugars.
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What are the two types of chemical exposure?
skin contact, ingestion, and inhalation.Breathing and inhaling into to the lungs is known as inhalation.To ingest anything orally is to ingest it.When anything comes into close proximity to the skin, skin contact occurs.
Which two categories of chemical dangers are most common?The dangers associated with employing chemicals are referred to as chemical hazards.There are two categories of chemical dangers at work:Hazards to physical and chemical systems
What are hazardous compounds and chemical hazards?Chemical and toxic compounds can cause a variety of physical and health risks, including irritability, sensitization, and carcinogenicity .
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What is the hydrogen ion concentration for a solution of ammonia, whose hydroxide ion concentration is 6.25×10−8 mol/L?
The hydrogen ion concentration of a solution of ammonia depends on the concentration of the hydroxide ions in the solution.
The hydrogen ion concentration of a solution of ammonia with a hydroxide ion concentration of 6.25 x 10-8 mol/L can be calculated using the equation Kw = [H+] [OH-], where Kw is the ion product constant for water. Using this equation, [H+] can be calculated by rearranging to [H+] = Kw/[OH-] and substituting the given values. This gives [H+] = 1.0 x 10-14/6.25 x 10-8, which equals 1.6 x 10-7 mol/L. Therefore, the hydrogen ion concentration for the given solution of ammonia is 1.6 x 10-7 mol/L.
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What is Scope 3 upstream and downstream?
Scope 3 emissions, also known as value chain emissions, are indirect GHG emissions both upstream and downstream of an organization’s main operations.
This normally means all of the emissions a company is responsible for outside of its operations from the goods it buys to the disposal of the products it sells.
With time passes out to make the drastic global emissions cuts required under the Paris Agreement, scope 3 offers a chance to drive rapid environmental engagement through supply chains, global and local businesses, local and national governments, and consumers.
There are various reasons beyond the urgent need for rapid global decarbonization that are driving organizations towards more accurate scope 3 emissions disclosure. Two of the key drivers are Science-Based Targets and Net-Zero pathways.
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Which claim most accurately describes the energy transformation taking place while he practices his guitar?
Sound energy is converted into elastic energy.
Kinetic energy is converted into thermal energy.
Mechanical energy is converted into sound energy.
Electrical energy is converted into mechanical energy.
There is a law called conservation of energy which states that energy can neither be created nor be destroyed. It can be only transferred from one form to another form. Therefore, the correct option is option B.
What is energy transfer in thermodynamics?Energy transfer is a phenomenon in which energy transfer from one matter to another matter. Energy can be transferred in two forms that are by doing work or by transferring heat.
Heat can be transferred by three ways conduction, convention and radiation. In conduction, when two object are in direct contact, transfer of molecules takes place. Kinetic energy is converted into thermal energy while he practices his guitar.
Therefore, the correct option is option B.
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Write the balanced chemical equation of the reaction between strong base and weak acid.
The balanced chemical equation between strong base and weak acid is represented as follows:
NaOH(aq)+ CH3COOH(aq)-----> CH3COONa(aq) + H2O(l)
When an acid reacts with a base, a salt is formed along with the formation of water, and this reaction is termed as neutralization reaction.
When a weak acid and a strong base are mixed, they react according to the following net-ionic equation: HA(aq) + OH⁻(aq) → A⁻(aq) + H₂O(l).
The balanced chemical equation between strong base and weak acid is represented as follows:
NaOH(aq)+ CH3COOH(aq)-----> CH3COONa(aq) + H2O(l)
Here, sodium hydroxide (NaOH) is a strong base and acetic acid (CH3COOH) is a weak acid.
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Which of the following represent the solubility of sugar in water at 20 degree Celsius 21 g 204 g 37 g 164 g?
The solubility of sugar in water at 20 degree Celsius is approximately 180 g/L.
What is solubility?Solubility is the ability of a substance to dissolve in a liquid or other solvent. This is an important property of chemical compounds because it affects the availability of a substance in various forms, such as in a solution, suspension, or solid. For example, sugar is more soluble in hot water than in cold water, meaning that more sugar can dissolve in hot water than in cold water. Solubility can be affected by the temperature, pressure, and the chemical and physical properties of the substances involved. In general, solubility increases as temperature increases, and decreases as pressure increases. Additionally, solubility may be affected by the pH of the solution or the presence of other compounds.
Therefore:
21 g: Soluble - 21 g of sugar is soluble in water at this temperature.
204 g: Insoluble - 204 g of sugar is more than the solubility limit at this temperature, so it is insoluble.
37 g: Soluble - 37 g of sugar is soluble in water at this temperature.
164 g: Insoluble - 164 g of sugar is more than the solubility limit at this temperature, so it is insoluble.
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which balloon, a or b, most accurately illustrates the effusion of a gas from the central balloon?
Balloon A indicates accurately illustrates the effusion of a gas from the central balloon.
The root mean square velocity of orange molecules is greater. As a result, they travel faster than blue molecules. They are more easily able to escape from balloons than blue ones. As a result, balloon A (with less orange and more blue) indicates proper effusion.
The root means square velocity v is given by the formula v = (3RT/M)1/2,
So,
v is proportional to (1/M)^1/2
The effusion rate is proportional to ( 1/M)^1/2
As a result, the rate of effusion is proportional to v. ( room means square velocity)
Relative rate of effusion for orange spheres compared to blue spheres
= (v of orange / v of blue)
= (495 m/s / 380 m/s)
= 1.303
As an outcome, the relative rate of effusion is 1.303. (orange is 1.303 times more effused than blue).
As a result, they travel at a faster rate than blue molecules. They are more easily able to escape from balloons than blue ones.
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Draw the major organic product of the reaction shown below. он +HBr You do not have to consider stereochemistry. You do not have to explicitly draw H atoms. opy aste ChemDoodle
The major organic product of the reaction shown below. он +HBr You do not have to consider stereochemistry. The product is Ether i.e. CH3−CH2−O−CH2−CH3.
Stereochemistry is a branch of chemistry that studies and manipulates the relative spatial arrangement of atoms within molecules. The study of interactions between stereoisomers, which have various structural formulas but the same chemical formula and arrangement of linked atoms (constitution) by definition, is known as stereochemistry (the three-dimensional orientations of their atoms in space). Due to the fact that the prefix "stereo-" signifies three-dimensionality, it is also known as 3D chemistry. Stereochemistry encompasses all of chemistry, including organic, inorganic, biological, physical, and especially supramolecular chemistry. Stereochemistry include techniques for identifying and defining these relationships, the effects these relationships have on the chemical or biological characteristics of the molecules in question, and how these relationships affect the reactivity of the molecules in question (dynamic stereochemistry). One important field of stereochemistry is the study of chiral compounds, or molecules lacking a plane of symmetry and not superposable on their mirror copies. The word "chiral," which is derived from the Greek word "cheir," which also denotes handedness, describes objects that have a "left-handed" and "right-handed" shape.
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consider the following reaction: pbco3(s)←−→pbo(s)+co2(g)
The given reaction : PbCO₃ (s)⇔ PbO(s) + CO₂ is an example of a decomposition reaction.
A decomposition reaction is a reaction in which two or more different products are formed from a single reactant. It involves the breakdown of a molecule into its simpler forms.
In general, metal carbonates when heated, decomposes to form a metal oxide with the release of carbon dioxide gas. Some metals can readily decompose while some might not.
In the above given reaction, lead carbonate (PbCO₃) which is a white amorphous powdery substance undergoes decomposition to produce the metal oxide i.e lead oxide and releases carbon dioxide gas.
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which statements is true about electrons in their energy levels?
a. electrons closer to the nucleus require more energy to remove.
b. elements with greater atomic mass require more ionization energy.
c. elements with small atomic radii easily gain electrons.
d. electrons are lost from the inner energy levels first.
Answer:
statements a and c are correct
What happens when lemon reacts with metal?
Metal micro-particle leaching can occur if lemon juice comes into prolonged contact with metals or metallic containers (even metals like stainless steel grade).
What is metals?Metals effectively conduct heat and electricity because they are bright, opaque materials.Lemon juice has an acidic character since it contains citric acid. When iron and citric acid mix, iron oxide and hydrogen gas are usually generated. Because of this, lemon juice cannot be consumed. Also reputed to be extremely caustic is lemon juice. If lemon juice is in touch with metals or metallic containers over an extended period of time, it may result in the leaching of microparticle metals (even metals like stainless steel quality). This may imply that a client may unintentionally consume a corrosion-related micro metal.For more information on metals kindly visit to
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The number of known elements changed very rapidly over a 150-year period. There were 62 known elements in the mid-1800s. How many known elements (total) are there today?.
There are 118 known chemical elements in the periodic table as of today.
Periodic table, often referred to as The Periodic Table of Elements, is rows and columns of chemical elements which are organized by its atomic number, from the element with the lowest atomic number namely hydrogen, to the highest element with the highest atomic number called oganesson. The Periodic Table was first arranged and formulated by a Russian chemist Dmitri Mendeleev in 1869. Periodic table is an important tool to organize and arrange chemical properties for each elements listed in the periodic table and also to predict chemical reaction as well as how each elements relate and react with one another.
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What intermolecular forces are present between two molecules of CH₃CF₃?
B) dispersion and dipole-dipole
Between two CH3CF3 molecules, dispersion and dipole-dipole intermolecular forces exist.
Due to CH3CF3's polar nature, two of its molecules will interact via dipole-dipole interactions. Because dispersion forces exist between every molecule, they will also be present. The electrostatic forces between two permanently polar molecules are called dipole-dipole forces, or dipole-dipole interactions. The forces of attraction that occur between molecules are referred to as intermolecular forces (IMF), sometimes known as secondary forces. Intramolecular forces, such as the bonds between atoms, are those that exist within a molecule and hold it together. The interactions between molecules, or intermolecular forces, are what control many of a substance's physical characteristics.
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What is the mass of 1.00 mol of each substance?
The mass of one mole of a substance is equal to that substance's molecular weight.
The molecular weight of a substance is equal to its mass in one mole. Water, for example, has a mean molecular weight of 18.015 atomic mass units (amu), implying that one mole of water weighs 18.015 grams. In the International System of Units, the mole (symbol mol) is the unit of substance amount (SI). The amount of substance is a measurement of how many elementary entities of a given substance are present in an object or sample. An elementary entity can be an atom, a molecule, an ion, an ion pair, or a subatomic particle such as an electron, depending on the substance.
The mole is widely used in chemistry to express quantities of reactants and products of chemical reactions. The term gram-molecule was formerly used for "mole of molecules", and gram-atom for "mole of atoms".
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What is modern symbols of elements?
Name of the element is represented by a symbol. One atom of the element is depicted by the symbol. Some symbols, like those for gold, copper, and potassium, are taken from the latin names of the elements.
What do the elements' contemporary emblems look like?Zinc, Zn, chlorine, etc. Other symbols were derived from Latin, Germanic, or Greek names of elements. For instance, the Latin term for iron is ferrum, while the symbols for sodium and potassium are natrium and kalium, respectively.
How do the modern's components fare?The elements are listed in the current periodic table according to their atomic number, not their relative atomic mass. The elements are grouped in rows, sometimes known as periods, in the periodic table.
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consider the following tetra-substituted cyclohexane:
A colorless, movable liquid with a light, sweet smell is cyclohexane. In addition to being somewhat soluble in alcohol, acetone, benzene, ethanol, ethyl ether, olive oil, and carbon tetrachloride, it is also somewhat soluble in water.
Six groups are present in the equatorial regions and another six groups are present in the axial groups, making the chair conformation structure the most stable conformation structure.
As seen in figure 1 The chair conformation will be stable when the bigger atoms or groups are at the equatorial position. This is because there is relatively little steric interaction between the atoms or groups. The bigger atoms or groups that are present at the equatorial position do not interact sterically.
The chair conformation structure in figure 2 is the stable conformation structure. Because the adjacent groups to the bulky groups are present in the axial location and the equatorial position of the bulky groups, the groups do not interact with one another.
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What is the molarity of sucrose c12h22o11 if 20g of it is dissolved in water to make the volume of the solution upto 2 Litres?
The molarity of sucrose c12h22o11 if 20g of it is dissolved in water to make the volume of the solution upto 2 Litres is 0.029 mol/L.
What is molarity, for instance?The moles of solute per liter of solution is measured as molarity. Molarity, also referred to as molar concentration, is denoted by the letter "M".
We divide the number of moles of solute by the total volume of liters of solution to determine the molarity of a solution.
For instance, when table salt is dissolved in water, water serves as both the solution and the solute. Sodium chloride weights 58.44 grams per mole. One molar solution, or 1M, is created by dissolving 58.44 grams of sodium chloride in one liter of water.
Molar mass of C₁₂H₂₂O₁₁ is
12(12) + 22(1) + 11(16)
= 342g/mol.
Molarity is defined as = Mass / Molar Mass × Volume.
Sugar (C₁₂H₂₂O₁₁) has a concentration of
20 / 342 2 = 0.029 mol/L.
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When did pewter stop using lead?
Older pewters with a higher lead content weigh more, tarnish more quickly, and develop a darker silver-grey colour with time. Through BS5140, which was strengthened by BSEN611 in 1994, lead was eliminated from the composition in 1974.
What is Lead ?
The periodic table's element lead has an atomic number of 82.
Humans have used lead (Pb), a metal, for countless years, going all the way back to 7000 BC.
The element can be found in trace amounts in a number of minerals, with the exception of sulphide and lead glance (PBS), which are used to make the metal all over the world.
Lead (Pb) is a white, soft, shiny metal that is very malleable.
The metal is not only a good conductor of electricity but also has a strong resistance to corrosion.
When burned in the air, the metal's powdered form emits a bluish-white blaze.
Lead fluoride is created when fluorine and lead are combined at ambient temperature.
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What causes solid to change to a liquid?
Answer:
heat
Explanation:
it causes the atoms to move faster and the bonds between them become looser, and the solid changes to a liquid.
When exposed to a chemical What should you do?
If you believe you may have inhaled a chemical, get outside right away.If a liquid chemical saturates skin or clothing, immediately remove clothing and thoroughly wash the affected area to remove the chemical.
What should you do initially if you are exposed to the a chemical?Get medical help right away.If this substance comes in touch with your skin, immediately wash it off with water.If this chemical gets on your clothing, take it off right away, and immediately wash your skin with water.After cleaning, seek medical assistance if the irritation continues.
How you'd do if chemical dangers put you in danger?Reduce contact with chemicals by donning gloves, a mask, or other safety gear.After utilising chemicals, always wash your hands using soap and warm water.
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Help pls I have this 100 question test and do not get this question pls helppp !!!
Answer:
The answer to your problem is B
Which sample of argon gas has the same number of atoms as a 100 ml gas at 1. 0 atm and 300k.
The sample of argon gas that has the same number of atoms as a 100 mL helium gas at 1.0 atm and 300 is 100. mL at 1.0 atm and 300. The correct option is D.
How many moles of gases are there in the samples that are provided?The ideal gas equation is used to determine the number of moles of gases in each of the provided gas samples.
The ideal gas equation is: PV/RT = n
where;
P is pressure, V is volume, n is number of moles of gas, T is temperature of gas, R is molar gas constant = 0.082 atm.L/mol/K
Moles of gas in the given helium gas sample:
P = 1.0 atm, V = 100 mL or 0.1 L, T = 300 K
n = PV/RT
n = (1 x 0.1 )/ (0.082 x 300)
n = 0.00406 moles
1 moles = 6.02x 10 ²³ number of atoms
For the argon gas sample:
A.
n = PV/RT
n = (1 x 0.05) / (0.082 x 300)
n = 0.00203 moles
B.
n = PV/RT
n = (0.5 x 0.05) / (0.082 x 300)
n = 0.00102 moles
C.
n = PV/RT
n = (0.5 x 0.1) / (0.082 x 300)
n = 0.00203 moles
D.
n = PV/RT
n = (1 x 0.1) / (0.082 x 300)
n = 0.00406 moles
Therefore, the sample of argon gas that has the same number of atoms as a 100 mL helium gas at 1.0 atm and 300 is 100. mL at 1.0 atm and 300. The correct option is D.
Your question is incomplete but most probably your full question was
Which sample of argon gas has the same number of atoms as a 100.-milliliter sample of helium gas at 1.0 atm and 300. K?
A) 50. mL at 1.0 atm and 300. K
B) 50. mL at 0.5 atm and 300. K
C) 100. mL at 0.5 atm and 300. K
D) 100. mL at 1.0 atm and 300. K
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If you have two objects that are relatively the same size, but when placed in water one
of the object sinks and the other floats. What can you predict based off this observation?
Answer:
it is it is because both of the items have different density which makes one of the item which are the lesser density float and the other item which is more density sink if the density of any item is more than the density of water it will always think and if the density of any substances less than the density of water it will float
an element X forms an oxide with formula X2O3
(a) state the valency of X
(b) write the formula of
The number of atoms of X in its oxide is 2 and that of oxygen is 3. The number of oxygen atoms in the oxide be the valency of the element X. Hence, the valency of the element X is 3.
What is valency?Valency of an atom is the number of electrons that have to be gained or lost from the atom to achieve octet. It is based on the number of valence electrons of the element.
If an element has 6 valence electrons, then it needs 2 more electrons to achieve octet hence, the valency is 2. Oxygen has a valency of 2 thus, it needs two electrons to be donated or shared by other atom.
The number oxygen in the oxide is the number of electrons required by the element X to achieve octet. Therefore, the valency of X is 3.
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Name The Alkyne Shown. CI- - CC Name:
The organic compound is an alkyl chloride. The IUPAC name of the given compound is 4- methyl-pent-2-yne chloride.
What are IUPAC rules?For naming organic compounds, there are certain rules regarding the numbering of carbon atoms and naming of adding functional groups to the names.
The given compound is an alkyne with triple bond. The numbering of carbon atom is started from the triple bonded end. Hence there are 6 carbons in the long chain. The methyl branch is attached to the 4th carbon in the long chain and Cl group is attached to the 5th carbon.
The triple bond is between the second and third carbon atoms.Therefore, the IUPAC name of the compound is 4- methyl-pent-2-yne chloride.
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