M.C.Q (1 Marks)

Question 11 Mark

Which of the following methods of preparation of amines will give same number of carbon atoms in the chain of amines as in the reactant?

Answer

$(a)$ Treatment of amide with bromine in an aqueous solution of sodium hydroxide
Explanation: Aliphatic and aryl$/$alkyl primary amines can be prepared by the reduction of the corresponding nitriles with lithium aluminium hydride $\ce{LiAIH_4}.$

Heating alkyl halide with primary, secondary, and tertiary amine can be prepared by reduction of $\ce{LiAlH_4}$ ether followed by treatment with water.

Heating alkyl halide with potassium salt of phthalimide followed by hydrolysis produces primary amine. This process is known as Gabriel's phthalimide reaction. The number of carbon atoms in the chain of amines of the product is the same as a reactant.

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Question 21 Mark

The conversion of an alkyl halide into alcohol by aqueous $NaOH$ is classified as

Answer

Alkyl halides on alkaline hydrolysis $($aqueous $NaOH)$ get converted into alcohol. This takes place by a nucleophilic substitution reaction where the $-X$ atom is substituted by a nucleophile i.e $-OH$ group. The primary alkyl halides undergo nucleophilic substitution reaction by $S_N2$ substitution mechanism, while tertiary alkyl halides follow $S_N1$ substitution mechanism.

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Question 31 Mark

Match the items given in column I with that in column II.

Column I	Column II
(a) Molarity	(1) $\frac{\text { Mass of solute }}{\text { Mass of solution }} \times 10^6$
(b) Molality	(2) Number of gram moles of a solute per litre of solution
(c)Normality	(3) Number of gram moles of a solute per kg of solvent
(d) ppm	iv) Number of gram equivalent of a solute per litre of solution

Answer

(a) (a)-(2), (b) - (3), (c) - (4), (d) - (1)
Explanation: (a) - (2), (b) - (3), (c) - (4), (d) - (1)

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Question 41 Mark

Which one of the following compounds is more reactive towards $S_N1$ reaction?

Answer

$C_6H_5CH(C_6H_5)^+$ carbocation formed is more stable.

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Question 51 Mark

A compound $(A)$ with molecular formula $C_5H_{10}O,$ forms a phenyl hydrazone and gives negative Tollens' and iodoform tests. The compound on reduction gives $n-$pentane. The compound $(A)$ is:

Answer

Pentan$-3-$one

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Question 61 Mark

Which of the following does not give Cannizaro reaction?

Answer

$(CH_3)_2 CH - CHO$ doesn't give cannizaro reaction.

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Question 71 Mark

Chlorine reacts with cold and dilute $NaOH$ to give

Answer

Chlorine reacts with cold and dilute $NaOH$ to produce a mixture of sodium chloride $(NaCl)$ and sodium hypochloride $(NaOCl).$
$2NaOH + Cl_2 \rightarrow NaCl + NaOCl + H_2O$

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Question 81 Mark

Anisole can be prepared by the action of methyl iodide on sodium phenate. The reaction is called

Answer

(c) Williamsons reaction
Explanation: The reaction of an alkyl halide with sodium alkoxide to give ether (alkoxy alkane), is known as Williamson's synthesis. In this reaction, an ether (anisole) is prepared by the action of alkyl halide (methyl iodide) on sodium alkoxide (sodium phenate), so it is an example of Williamson's synthesis.

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Question 91 Mark

β-pleated sheet structure in proteins refers to

Answer

(d) secondary structure
Explanation: Alpha helices and beta sheets are the two most known secondary structures of protein, As the protein folds into a three-dimensional structure, the secondary structure forms an intermediate.

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Question 101 Mark

The half life of a substance in a first order reaction is $15 \min.$ The rate constant is

Answer

$4.62 \times 10^{-2} \min ^{-1}$
Explanation: for first order reaction
$t_{1 / 2}=\frac{0.693}{k}$

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Question 111 Mark

The incorrect statement about interstitial compounds is:

Answer

(c) They are chemically reactive.
Explanation: Interstitial compounds are obtained when small atoms like H, B, C, resemble N, etc. fit into the lattice of other elements. They are chemically inert

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Question 121 Mark

The ionic reactions are generally very fast because

Answer

(a) It does not involve bond breaking
Explanation: Ionic reactions do not involve bond breaking, energy is directly used in completing the reaction, therefore they are fast.

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Chemistry M.C.Q (1 Marks)

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