M.C.Q (1 Marks)

Question 11 Mark

Match the item given in Column I with expression given in Column II

Column I	Column II
(a) Osmotic Pressure	$p = K _{ H } \cdot \chi_{ B }$
(b) Relative lowering of vapour pressure	$\frac{\Delta P }{ P _A^o}=\chi_{ B }$
(c) Henry Law	$\Delta T _{ b }= K _{ b } \cdot m$
(d) Elevation in boiling point	p = iCRT

Answer

(d) (a)-(iv), (b) - (ii), (c) - (i), (d) - (iii).
Explanation: (a)-(iv), (b) - (ii), (c) - (i), (d) - (iii).

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Question 21 Mark

In the reaction

Answer

(d) All of these
Explanation: Phenol reacts with sodium hydroxide solution to give a colourless solution containing sodium phenoxide. In this reaction, the hydrogen ion has been removed by the strongly basic hydroxide ion in the sodium hydroxide solution.

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Question 31 Mark

Isomers of the compound $\ce{C4H9Br}$ are:

Answer

$(c) 1-$Bromobutane$, 2 - $Bromobutane$, 1-$ bromo$-2-$methylpropane, and $2-$bromo$-2-$methylpropane
Explanation: Isomers are compounds having the same molecular formula but different structures. In the given straight$-$chain $4-C$ compounds$, Br$ is placed at different positions but the molecular formula is same.

In the given branched $4-C$ compounds, there is a branching of $-CH3$ at carbon $2$ but $Br$ is placed at positions $1$ and $2$ respectively.

So, all of these are isomers since they have the same molecular formula but different structures.

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Question 41 Mark

When diethyl ether is heated with excess of HI, it produces :

Answer

(a) ethyl iodide
Explanation: ethyl iodide

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Question 51 Mark

Which of the following does not give silver mirror test?

Answer

$\ce{CH_3COCH_3}$ will not give a silver mirror test $($Tollens Test$).$ Tollens test is given by aldehydes only and $HCOOH$ is the only acid that gives tollen's test. Ketones do not give tollen's test.

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Question 61 Mark

The half-life of a reaction is halved as the initial concentration of the reactant is doubled. The order of the reaction is:

Answer

For $2^{nd}$ order reaction, the half-life is inversely related to the concentration of the reactant. $t_{1/2}$ for second order reaction $\alpha \frac{1}{[R]}$

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Question 71 Mark

Which one among the following metals of 3d series has the lowest melting point?

Answer

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Question 81 Mark

Which of the following is a disaccharide?

Answer

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Question 91 Mark

Gabriel synthesis is used for the preparation of:

Answer

In Gabriel Phthalimide reaction, the sodium or potassium salt of phthalimide is $N-$alkylated with a primary alkyl halide to give the corresponding $N-$alkylphthalimideis for producing primary amines. This is because of the reaction of sodium or potassium salt of phthalimide with alkyl halide impure $SN_2$ reaction

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Question 101 Mark

Value of Henry's constant $K_H:$

Answer

Value of henry constant increases with increase in temperature.

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Question 111 Mark

Chloromethane on treatment with excess of ammonia yields mainly

Answer

$\ce{CH_3Cl + NH_3 \rightarrow CH_3NH_2 + HCl}$
Ammonia molecule is a nucleophile in nature as it has unpaired electrons. This nucleophile attacks the chloromethane $\ce{CH_3Cl}$ molecule and forms methylamine or methenamine by a nucleophilic substitution reaction mechanism. The carbon atom is partially positive in the molecule, due to the electronegativity of the halide attached which is partially negative. The electron- rich nucleophile attacks the positive ion, causing the halide ion to be separated from the molecule.

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Question 121 Mark

The fragrance of the aldehyde and ketone are used for perfume and similar uses depend on:

Answer

(b) size and solubility of the aldehyde and ketone molecule.
Explanation: Size and solubility of aldehyde and ketone determine fragrance. For example, aldehyde C-10 is used in floral blends like rose, jasmine, etc. While aldehyde C-11 has a strong citrus smell and aldehyde C-16 has a strong strawberry smell.

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Chemistry M.C.Q (1 Marks)

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