NEET UG 2007 — Chemistry Physical Chemistry

2007mcqhard

0.5 molal aqueous solution of a weak acid $(\mathrm{HX})$ is $20 \%$ ionised. If $\mathrm{K}_f$ for water is $1.86 \mathrm{Kg} \mathrm{mol}^{-1}$ , the lowering in freezing point of the solution is:

Official previous-year question

Held on 30 Apr 2007 · Verified 9 Jul 2026.

Options

A
$0.56 \mathrm{~K}$
B
$1.12 \mathrm{~K}$
C
$-0.56 \mathrm{~K}$
D
$-1.12 \mathrm{~K}$

Did you get this right?

Solution

$\operatorname{As} \Delta \mathrm{T}_f=i k_f \mathrm{~m}$ For $\begin{aligned} & \mathrm{HX} \rightleftharpoons \mathrm{H}^{+}+\mathrm{X}^{-} \\ & t=0 \quad 1 \quad 0 \quad 0 \\ & \begin{array}{llll} t_{\text {eq }} & (1-0.20) & 0.20 & 0.20 \end{array} \\ & \end{aligned}$ Total no. of moles $=1-0.20+0.20$ $\begin{aligned} +0.20 & =1+0.20=1.2 \\ \therefore \Delta \mathrm{T}_f & =1.2 \times 1.86 \times 0.5 \\ & =1.1160 \end{aligned}$ Related Theory The boiling point and freezing point are colligative properties. Due to the addition of solutes, the boiling point tends to increase, and freezing point tends to decrease.

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NEET UG 2007 — Chemistry Physical Chemistry

2007mcqhard

0.5 molal aqueous solution of a weak acid $(\mathrm{HX})$ is $20 \%$ ionised. If $\mathrm{K}_f$ for water is $1.86 \mathrm{Kg} \mathrm{mol}^{-1}$ , the lowering in freezing point of the solution is:

Official previous-year question

Held on 30 Apr 2007 · Verified 9 Jul 2026.

Options

A
$0.56 \mathrm{~K}$
B
$1.12 \mathrm{~K}$
C
$-0.56 \mathrm{~K}$
D
$-1.12 \mathrm{~K}$

Did you get this right?

Solution

Your note

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NEET UG 2007 — Chemistry Physical Chemistry

Options

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Solution

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NEET UG Physical Chemistry in other years

More NEET UG Physical Chemistry questions

Other Chemistry topics for NEET UG

Organic Chemistry

Inorganic Chemistry

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