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2022 9 questions

Q822022 · 29 Jul 2022 · Shift 2· Numerical answer
$1.80 g$ of solute A was dissolved in $62.5 c m^{3}$ of ethanol and freezing point of the solution was found to be $155.1 K$ . The molar mass of solute A is ____ $g mo l^{- 1}$ . [Given : Freezing point of ethanol is $156.0 K$ . Density of ethanol is $0.80 g c m^{- 3}$ . Freezing point depression constant of ethanol is $2.00 K kg mo l^{- 1}$ ]
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Answer: 80
Q832022 · 28 Jul 2022 · Shift 1· Numerical answer
$150 g$ of acetic acid was contaminated with $10.2 g$ ascorbic acid ( $C_{6} H_{8} O_{6}$ ) to lower down its freezing point by $(x \times 1 0^{- 1})^{\circ} C$ . The value of $x$ is _________. (Nearest integer) [Given $K_{f} = 3.9 K kg mol^{- 1}$ ; molar mass of ascorbic acid $= 176 g mol^{- 1}$ ]
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Answer: 15
Q642022 · 27 Jul 2022 · Shift 1
Boiling point of a $2%$ aqueous solution of a non-volatile solute A is equal to the boiling point of $8%$ aqueous solution of a non-volatile solute B. The relation between molecular weights of A and B is
1. A. $M_{A} = 4 M_{B}$
2. B. $M_{B} = 4 M_{A}$
3. C. $M_{A} = 8 M_{B}$
4. D. $M_{B} = 8 M_{A}$
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Answer: B
Q622022 · 25 Jul 2022 · Shift 2
Two solutions A and B are prepared by dissolving 1 g of non-volatile solutes X and Y, respectively in 1 kg of water. The ratio of depression in freezing points for A and B is found to be 1 : 4. The ratio of molar masses of X and Y is
1. A.1 : 4
2. B.1 : 0.25
3. C.1 : 0.20
4. D.1 : 5
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Answer: B
Q822022 · 28 Jun 2022 · Shift 2· Numerical answer
$2.5 g$ of protein containing only glycine ( $C_{2} H_{5} N O_{2}$ ) is dissolved in water to make $500 mL$ of solution. The osmotic pressure of this solution at $300 K$ is found to be $5.03 \times 1 0^{- 3} bar$ . The total number of glycine units present in the protein is ____. (Given : $R = 0.083 L bar K^{- 1} mo l^{- 1}$ )
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Answer: 330
Q822022 · 27 Jun 2022 · Shift 1· Numerical answer
$2 g$ of a non-volatile non-electrolyte solute is dissolved in $200 g$ of two different solvents A and B whose ebullioscopic constants are in the ratio of $1 : 8$ . The elevation in boiling points of A and B are in the ratio $\frac{x}{y} (x : y)$ . The value of $y$ is ____. (Nearest integer)
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Answer: 8
Q842022 · 27 Jun 2022 · Shift 2· Numerical answer
A solution containing $2.5 \times 1 0^{- 3} kg$ of a solute dissolved in $75 \times 1 0^{- 3} kg$ of water boils at $373.535 K$ . The molar mass of the solute is ________ $g mol^{- 1}$ . [nearest integer] (Given : $K_{b} (H_{2} O) = 0.52 K kg mol^{- 1}$ and boiling point of water $= 373.15 K$ )
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Answer: 45
Q842022 · 26 Jun 2022 · Shift 2· Numerical answer
The osmotic pressure exerted by a solution prepared by dissolving $2.0 g$ of protein of molar mass $60 kg mo l^{- 1}$ in $200 mL$ of water at $2 7^{\circ} C$ is ____ $Pa$ . [integer value] (use $R = 0.083 L bar mo l^{- 1} K^{- 1}$ )
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Answer: 415
Q632022 · 25 Jun 2022 · Shift 2
Solute A associates in water. When $0.7 g$ of solute A is dissolved in $42.0 g$ of water, it depresses the freezing point by $0. 2^{\circ} C$ . The percentage association of solute A in water, is : [Given : Molar mass of $A = 93 g mo l^{- 1}$ . Molal depression constant of water is $1.86 K kg mo l^{- 1}$ .]
1. A.50%
2. B.60%
3. C.70%
4. D.80%
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Answer: D