The addition of a catalyst during a chemical reaction alters which of the following quantities?
a.
Internal energy
b.
Enthalpy
c.
Activation energy
Correct Answer
d.
Entropy
Step-by-Step AI Explanation
Verified Method
Catalyst lowers the threshold point by providing an alternative pathway with a lower activation energy.
Q2mcq
Predict the correct order among the following:
a.
lone pair-lone pair > bond pair-bond pair > lone pair – bond pair
b.
bond pair – bond pair > lone pair – bond pair > lone pair – lone pair
c.
lone pair – bond pair > bond pair – bond pair > lone pair – lone pair
d.
lone pair – lone pair > lone pair – bond pair > bond pair – bond pair
Correct Answer
Step-by-Step AI Explanation
Verified Method
According to VSEPR theory, repulsion strength is: lone pair-lone pair > lone pair-bond pair > bond pair-bond pair because lone pair electrons occupy more space.
Q3mcq
The correct statement regarding the basicity of arylamines is:
a.
Arylamines are generally more basic than alkylamines because the nitrogen lone-pair electrons are not delocalized by interaction with the aromatic ring pi electron system.
b.
Arylamines are generally more basic than alkylamines because of aryl group.
c.
Arylamines are generally more basic than alkylamines, because the nitrogen atom in arylamines is sp-hybridized
d.
Arylamines are generally less basic than alkylamines because the nitrogen lone-pair electrons are delocalized by interaction with the aromatic ring pi electron system.
Correct Answer
Step-by-Step AI Explanation
Verified Method
In arylamines, the lone pair on nitrogen is delocalized into the aromatic ring via resonance, making it less available for donation compared to alkylamines.
Q4mcq
When copper is heated with conc. HNO3 it produces:
a.
Cu(NO3)2 and NO
b.
Cu(NO3)2, NO and NO2
c.
Cu(NO3)2 and N2O
d.
Cu(NO3)2 and NO2
Correct Answer
Step-by-Step AI Explanation
Verified Method
Reaction: Cu + 4HNO3 (conc.) -> Cu(NO3)2 + 2H2O + 2NO2. Reddish brown NO2 gas is evolved.
Q5mcq
For the following reactions: (a) CH3CH2CH2Br + KOH -> CH3CH = CH2 + KBr + H2O; (b) (CH3)2CHBr + KOH -> (CH3)2CHOH + KBr; (c) C6H6 + Br2 -> C6H6Br2. Which of the following statements is correct?
a.
(a) is elimination, (b) is substitution and (c) addition reaction.
Correct Answer
b.
(a) is elimination, (b) and (c) are substitution reactions.
c.
(a) is substitution, (b) and (c) are addition reactions.
d.
(a) and (b) are elimination reactions and (c) is addition reaction.
Step-by-Step AI Explanation
Verified Method
(a) is dehydrohalogenation (elimination), (b) is nucleophilic substitution, and (c) is addition across a double bond.
Q6mcq
Two electrons occupying the same orbital are distinguished by:
a.
Magnetic quantum number
b.
Azimuthal quantum number
c.
Spin quantum number
Correct Answer
d.
Principal quantum number
Step-by-Step AI Explanation
Verified Method
According to Pauli's Exclusion Principle, no two electrons in an atom can have the same four quantum numbers. If they occupy the same orbital (n, l, ml are identical), they must differ in spin quantum number (ms).
Q7mcq
The reaction of phenoxide ion (from phenol + NaH) with methyl iodide (Me-I) to form an ether can be classified as:
Match the compounds given in column I with the hybridisation and shape given in column II and mark the correct option. (Column I: (a) XeF6, (b) XeO3, (c) XeOF4, (d) XeF4; Column II: (i) distorted octahedral, (ii) square planar, (iii) pyramidal, (iv) square pyramidal)
a.
(a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)
b.
(a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)
c.
(a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
d.
(a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)
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The correct statement regarding a carbonyl compound with a hydrogen atom on its alpha-carbon, is:
a.
a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as aldehyde-ketone equilibration.
b.
a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as carbonylation
c.
a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as keto-enol tautomerism.
d.
a carbonyl compound with a hydrogen atom on its alpha-carbon never equilibrates with its corresponding enol.
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Match items of Column I with the items of Column II and assign the correct code: Column I (a) Cyanide process (b) Froth floatation process (c) Electrolytic reduction (d) Zone refining. Column II (i) Ultrapure Ge (ii) Dressing of Zns (iii) Extraction of Al (iv) Extraction of Au (v) Purification of Ni
a.
(1) (ii) (iii) (i) (v)
b.
(2) (i) (ii) (iii) (iv)
c.
(3) (iii) (iv) (v) (i)
d.
(4) (iv) (ii) (iii) (i)
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Equal moles of hydrogen and oxygen gases are placed in a container with a pin-hole through which both can escape. What fraction of the oxygen escapes in the time required for one-half of the hydrogen to escape?
a.
1/4
b.
3/8
c.
1/2
d.
1/8
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Which of the following statements about the composition of the vapour over an ideal 1:1 molar mixture of benzene and toluene is correct? Assume that the temperature is constant at 25ºC. (Given, Vapour Pressure Data at 25ºC, benzene = 12.8 kPa, toluene = 3.85 kPa)
a.
The vapour will contain a higher percentage of toluene
b.
The vapour will contain equal amounts of benzene and toluene
c.
Not enough information is given to make a prediction
d.
The vapour will contain a higher percentage of benzene
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MY and NY3, two nearly insoluble salts, have the same Ksp values of 6.2 × 10^-13 at room temperature. Which statement would be true in regard to MY and NY3?
a.
The molar solubility of MY in water is less than that of NY3
b.
The salts MY and NY3 are more soluble in 0.5 M KY than in pure water
c.
The addition of the salt of KY to solution of MY and NY3 will have no effect on their solubilities
d.
The molar solubilities of MY and NY3 in water are identical
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The rate of a first order reaction is 0.04 mol l⁻¹ s⁻¹ at 10 seconds and 0.03 mol l⁻¹ s⁻¹ at 20 seconds after initiation of the reaction. The half-life period of the reaction is:
a.
34.1 s
b.
44.1 s
c.
54.1 s
d.
24.1 s
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The rate of a first order reaction is 0.04 mol l^–1 s^–1 at 10 seconds and 0.03 mol l^–1 s^–1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is:
a.
34.1 s
b.
44.1 s
c.
54.1 s
d.
24.1 s
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