The depression in freezing point observed for a formic acid solut… - Vidyadip

MCQ

The depression in freezing point observed for a formic acid solution of concentration $0.5\,mL\,L ^{-1}$ is $0.0405^{\circ}\,C$. Density of formic acid is $1.05\,g\,mL ^{-1}$. The Van't Hoff factor of the formic acid solution is nearly: (Given for water $k _{ f }=1.86\,K\,kg\,mol ^{-1}$ )

A
$0.8$
B
$1.1$
✓
$1.9$
D
$2.4$

✓

Answer

Correct option: C.

$1.9$

c
$[ HCOOH ]=0.5\,ml\,1^{-1}$

$\Rightarrow\left(0.5 ml \times 1.05\,g\,ml ^{-1}\right) HCOOH$ in $1 L$

$\Rightarrow 0.525\,g\,HCOOH$ in $1\,L$

$m =\frac{(0.525 / 46)}{1\,kg } mol$ [Assuming dilute solution]

$\therefore \Delta T _{ f }= iK _{ f } m \Rightarrow i =\frac{\Delta T _{ f }}{ k _{ f } m }=\frac{0.0405 \times 46}{1.86 \times 0.525}=1.9$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from 1. Solution and colligative properties→1. Solution and colligative properties — all question types→Chemistry STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

What would be magnetic moment of Gd⁺³(Z = 64)?

A zinc metal sample containing zinc chloride as impurity was made to react with an excess of dilute hydrochloric acid at 27°C. Liberated hydrogen gas is collected at 760mm Hg pressure that occupies 780.0cm³ volume. If the vapour pressure of water at 27°C is 14mm Hg, what is the volume of H₂ at STP? The Standard pressure is 760mm Hg (molar volume of gas at standard temperature and pressure, STP = 22.4dm³)

Glucose contains

$ROH + HX \to RX + H_2O$
In the above reaction, the reactivity order of hydrogen halides is

The number of essential amino acids in man is

A nitrogen containing organic compound on heating with chloroform and alcoholic $KOH$, evolved very unpleasant smelling vapour. The compound could be

In pyrophosphoric acid number of hydroxyl group are

For dry cleaning of clothes instead of tetrachloroethane which is carcinogen in nature, which of the following solvents can be used?

$\begin{array}{*{20}{c}}
{{{(C{H_3})}_2}CH - C - N{H_2}\,\xrightarrow[{B{r_2}}]{{NaOH}}A\xrightarrow{{COC{l_2}}}B} \\
{||\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}
\end{array}$ $B$ is

Ammonia gas can be collected by the displacement of