Chemistry 2016 Jamb Examination
Chemistry 2016 Jamb Examination
Question 1
In an electrochemical cell, polarization is caused by
The correct option is B. Hydrogen.
Polarization in an electrochemical cell occurs when hydrogen gas accumulates on the surface of the electrode, preventing further reaction. This buildup increases the internal resistance of the cell and reduces its efficiency. Hence, hydrogen is responsible for polarization.
Polarization in an electrochemical cell occurs when hydrogen gas accumulates on the surface of the electrode, preventing further reaction. This buildup increases the internal resistance of the cell and reduces its efficiency. Hence, hydrogen is responsible for polarization.
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Question 2
The condition required for corrosion to take place is the presence of
The correct option is B. Water and Oxygen.
Corrosion, especially rusting of iron, requires both water and oxygen. Water acts as an electrolyte for ion transfer, while oxygen participates in the oxidation reaction leading to rust formation (iron(III) oxide).
Corrosion, especially rusting of iron, requires both water and oxygen. Water acts as an electrolyte for ion transfer, while oxygen participates in the oxidation reaction leading to rust formation (iron(III) oxide).
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Question 3
The enzyme used in the hydrolysis of starch to dextrin and maltose is
The correct option is C. Amylase.
Amylase catalyzes the hydrolysis of starch into smaller polysaccharides like dextrin and disaccharides like maltose. It is secreted by the salivary glands and pancreas in humans.
Amylase catalyzes the hydrolysis of starch into smaller polysaccharides like dextrin and disaccharides like maltose. It is secreted by the salivary glands and pancreas in humans.
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Question 4
In the laboratory preparation of chlorine from concentrated hydrochloric acid in the presence of potassium tetraoxomanganate(VII), the gas produced is dried by passing it through
The correct option is A. Concentrated tetraoxosulphate(VI) acid.
Concentrated \( \text{H}_2\text{SO}_4 \) is used to dry chlorine gas because it is an excellent dehydrating agent and does not react with chlorine. Other drying agents like calcium oxide or sodium hydroxide react with chlorine, making them unsuitable.
Concentrated \( \text{H}_2\text{SO}_4 \) is used to dry chlorine gas because it is an excellent dehydrating agent and does not react with chlorine. Other drying agents like calcium oxide or sodium hydroxide react with chlorine, making them unsuitable.
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Question 5
The monomer of nylon is
The correct option is B. Hexanedioic acid.
Nylon is formed by the condensation polymerization of hexanedioic acid (adipic acid) and hexamethylenediamine. These monomers link together to form long polymer chains with amide bonds.
Nylon is formed by the condensation polymerization of hexanedioic acid (adipic acid) and hexamethylenediamine. These monomers link together to form long polymer chains with amide bonds.
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Question 6
The principle of column chromatography is based on the ability of the constituents to
The correct option is D. Move at different speeds in the column.
Column chromatography separates mixtures based on differences in the rates at which components move through a stationary phase under the influence of a mobile phase (solvent). The varying speeds lead to separation of components.
Column chromatography separates mixtures based on differences in the rates at which components move through a stationary phase under the influence of a mobile phase (solvent). The varying speeds lead to separation of components.
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Question 7
Ammonium chloride can be separated from its mixture with common salt by
The correct option is D. Sublimation.
Ammonium chloride \( (\text{NH}_4\text{Cl}) \) sublimes upon heating, changing directly from solid to gas, while common salt \( (\text{NaCl}) \) does not. This allows the two substances to be separated by sublimation.
Ammonium chloride \( (\text{NH}_4\text{Cl}) \) sublimes upon heating, changing directly from solid to gas, while common salt \( (\text{NaCl}) \) does not. This allows the two substances to be separated by sublimation.
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Question 8
The ability of carbon to form long chains is referred to as
The correct option is D. Catenation.
Catenation is the property of an element (especially carbon) to form long chains or rings by bonding with itself through covalent bonds. This property accounts for the vast number of organic compounds.
Catenation is the property of an element (especially carbon) to form long chains or rings by bonding with itself through covalent bonds. This property accounts for the vast number of organic compounds.
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Question 9
The industrial preparation of hydrogen gas from water gas is referred to as
The correct option is A. Bosch process.
In the Bosch process, water gas (a mixture of \( \text{CO} \) and \( \text{H}_2 \)) reacts with steam to produce additional hydrogen gas and carbon dioxide:
\[ \text{CO} + \text{H}_2\text{O} \rightarrow \text{CO}_2 + \text{H}_2 \]This method is used industrially for hydrogen production.
In the Bosch process, water gas (a mixture of \( \text{CO} \) and \( \text{H}_2 \)) reacts with steam to produce additional hydrogen gas and carbon dioxide:
\[ \text{CO} + \text{H}_2\text{O} \rightarrow \text{CO}_2 + \text{H}_2 \]This method is used industrially for hydrogen production.
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Question 10
The relative atomic mass of a naturally occurring lithium consisting of 90% \( ^7\text{Li} \) and 10% \( ^6\text{Li} \) is
The correct option is D. 6.9.
Given:
\( ^7\text{Li} = 7 \), abundance = 90% = 0.9
\( ^6\text{Li} = 6 \), abundance = 10% = 0.1
Average atomic mass:
(0.9 × 7) + (0.1 × 6) = 6.3 + 0.6 = 6.9
 Hence, the relative atomic mass is 6.9.
Given:
\( ^7\text{Li} = 7 \), abundance = 90% = 0.9
\( ^6\text{Li} = 6 \), abundance = 10% = 0.1
Average atomic mass:
(0.9 × 7) + (0.1 × 6) = 6.3 + 0.6 = 6.9
 Hence, the relative atomic mass is 6.9.
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