Some Basic Concepts of Chemistry

Assertion (A): Equal moles of different substances contain same number of constituent particles.

Reason (R) : Equal weights of different substances contain the same number of constituent particles.

The correct answer is

• Both (A) and (R) are true and (R) is the correct explanation of (A)

• Both (A) and (R) are true but (R) is not the correct explanation of (A).

• (A) is true, but (R) is false

• (A) is false but (R) is true

Match the following:

The correct match is

• A - iv; B - i; C - ii; D - iii

• A - v; B - i; C - ii; D - iii

• A - iv; B - i; C - iii; D - ii

• A - i; B - iv; C - ii; D - iii

138 g of ethyl alcohol is mixed with 72 g of water. The ratio of mole fraction of alcohol to water is

• 3 :4

• 1: 2

• 1:4

• 1: 1

1.5 g of CdCl₂ was found to contain 0.9 g of Cd. Calculate the atomic weight of Cd.

• 118

• 112

• 106.5

• 53.25

One percent composition of an organic compound A is, carbon : 85.71% and hydrogen 14.29%. Its vapour density is 14. Consider the following reaction sequence-

$\underline{\mathrm{A}} \stackrel{{\mathrm{Cl}}_2/ {\mathrm{H}}_2\mathrm{O}}{\to } \underline{\mathrm{B}} \underset{\left(\mathrm{ii}\right) {\mathrm{H}}_3{\mathrm{O}}^{+}}{\overset{\left(\mathrm{i}\right) \mathrm{KCN}/ \mathrm{EtOH}}{\to }} \underline{C}$

Identify $\underline{\mathrm{C}}$.

• CH₃CH(OH)-CO₂H

• HO-CH₂-CH₂-CO₂H

• HO-CH₂-CO₂H

• CH₃-CH₂-CO₂H

At 25°C, the molar conductances at infinite dilution for the strong electrolytes NaOH, NaCl and BaCl₂ are 248 × 10^-4, 126 × 10^-4 and 280 × 10^-4 Sm² mol^-1 respectively, ${\mathrm{\lambda }}_{\mathrm{m}}^{°}$ (BaOH)₂ in Sm² mol^-1 is

• 52.4 × 10^-4

• 524 × 10^-4

• 402 × 10^-4

• 262 × 10^-4

The number of molecules of CO₂ liberated by the complete combustion of 0.1 g atom of graphite in air is

• 3.01 × 10²²

• 6.02 × 10²³

• 6.02 × 10²²

• 3.01 × 10²³

19 g of a mixture containing NaHCO₃ and Na₂CO₃ on complete heating liberated 1.12 L of CO₂ at STP. The weight of the remaining solid was 15.9 g. What is the weight (in g) of Na₂CO₃ in the mixture before heating?

• 8.4

• 15.9

• 4.0

• 10.6

Solution 'X' contains Na₂CO₃ and NaHCO₃, 20 mL of X when titrated using methyl orange indicator consumed 60 mL of 0.1 M HCl solution. In another experiment, 20 mL of X solution when titrated using phenolphthalein, consumed 20 mL of 0.1 M HCl solution. The concentrations (in mol L^-1) of Na₂CO₃ and NaHCO₃ in X are respectively

• 0.01, 0.02

• 0.1, 0.1

• 0.01, 0.01

• 0.1, 0.01

The number of moles of electrons required to deposit 36 g of Al from an aqueous solution of Al(NO₃)₃ is (At. wt. of Al = 27)

• 4

• 3

• 2

• 1