🏫 Board🧪 Chemistry

Arrange the following solutions in order of their increasing boiling points \(\left(\mathrm{i}\right){10}^{-4}\mathrm{M}…

Q1 FREE PREVIEW

Arrange the following solutions in order of their increasing boiling points

\(\left(\mathrm{i}\right){10}^{-4}\mathrm{M}\mathrm{NaCl}\\ \left(\mathrm{ii}\right){10}^{-4}\mathrm{M}\mathrm{Urea}\\ \left(\mathrm{iii}\right){10}^{-3}\mathrm{M}\mathrm{NaCl}\\ \left(\mathrm{iv}\right){10}^{-2}\mathrm{M}\mathrm{NaCl}\)

a

(ii) < (i) = (iii) < (iv)

b

(iv) < (iii) < (i) < (ii)

c

(ii) < (i) < (iii) < (iv)

d

(i) < (ii) < (iii) < (iv)

✓ Correct answer: c)

(ii) < (i) < (iii) < (iv)

Explanation

\(∆{\mathrm{T}}_{\mathrm{b}}={\mathrm{iK}}_{\mathrm{b}}\mathrm{m}\)

\(∆{\mathrm{T}}_{\mathrm{b}}\alpha \mathrm{i}\times \mathrm{m}\)

For NaCl " i " = 2 and Urea " i " = 1

Higher the product of vant Hoff factor and concentration higher the boiling point.

i × C = (i) 2 × 10–4 (ii) 1 × 10–4 (iii) 2 × 10–3 (iv) 2 × 10–2

Hence the order for boiling point is: (ii) < (i) < (iii) < (iv)

Practice more Board Chemistry PYQs

See every question on Solutions, or browse the full Board question bank.

See all questions on Solutions →