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CHXII02:SOLUTIONS

319441 The lubricating action of an oil is more if it possesses:

1 High vapour pressure

2 Low vapour pressure

3 High surface tension

4 High density

CHXII02:SOLUTIONS

319442 For an ideal binary liquid mixture

1

Δ S_{(m i x)} = 0; Δ G_{(m i x)} = 0

2

Δ H_{(m i x)} = 0; Δ S_{(m i x)} < 0

3

Δ V_{(m i x)} = 0; Δ G_{(m i x)} > 0

4

Δ S_{(m i x)} > 0; Δ G_{(m i x)} < 0

Explanation:

For an ideal solution; $Δ H = 0 a n d Δ V = 0$
$F r o m, Δ G = Δ H - T Δ S$
$Δ G = - v e$
Hence, $Δ G < 0 a n d Δ S > 0$

KCET - 2014

CHXII02:SOLUTIONS

319443 Benzene and toluene form nearly ideal solution. At $20^{\circ} C$ , the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at $20^{\circ} C$ for a solution containing 78 g of benzene and 46 g of toluene (in torr) is

1 50

2 25

3 37.5

4 53.5

Explanation:

$G i v e n t h a t,$
$V a p o u r p r e s s u r e o f b e n z e n e, P_{B e n z e n e}^{o} = 75 t o r r$
$V a p o u r p r e s s u r e o f t o l u e n e, P_{t o l u e n e}^{^{\circ}} = 22 t o r r$
$M o l a r m a s s o f b e n z e n e = 78 g m o l^{- 1}$
$M o l a r m a s s o f t o l u e n e = 92 g m o l^{- 1}$
$W e i g h t o f b e n z e n e = 78 g$
$W e i g h t o f t o l u e n e = 46 g$
$P_{B e n z e n e} = ?$
$\frac{\begin{array}{l} P_{B e n z e n e}^{o} - P_{B e n z e n e} \end{array}}{P_{B e n z e n e}^{o}} = x_{t o l u e n e}$
$\frac{75 - P_{B e n z e n e}}{75} = \frac{\frac{46}{92}}{\frac{46}{92} + \frac{78}{78}} = \frac{0.5}{1.5} = \frac{1}{3}$
$3 (75 - P_{B e n z e n e}) = 75 \Rightarrow P_{B e n z e n e} = 50 t o r r$

CHXII02:SOLUTIONS

319444 I. n-hexane + n-heptane
II. acetone + ethanol
III. bromoethane + chloroethane
IV. benzene + toluene
Which of the following combination is an example of ideal solutions ?

1 I, II, III

2 II, III, IV

3 I, III, IV

4 I, II, IV

CHXII02:SOLUTIONS

319441 The lubricating action of an oil is more if it possesses:

1 High vapour pressure

2 Low vapour pressure

3 High surface tension

4 High density

CHXII02:SOLUTIONS

319442 For an ideal binary liquid mixture

1

Δ S_{(m i x)} = 0; Δ G_{(m i x)} = 0

2

Δ H_{(m i x)} = 0; Δ S_{(m i x)} < 0

3

Δ V_{(m i x)} = 0; Δ G_{(m i x)} > 0

4

Δ S_{(m i x)} > 0; Δ G_{(m i x)} < 0

Explanation:

For an ideal solution; $Δ H = 0 a n d Δ V = 0$
$F r o m, Δ G = Δ H - T Δ S$
$Δ G = - v e$
Hence, $Δ G < 0 a n d Δ S > 0$

KCET - 2014

CHXII02:SOLUTIONS

319443 Benzene and toluene form nearly ideal solution. At $20^{\circ} C$ , the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at $20^{\circ} C$ for a solution containing 78 g of benzene and 46 g of toluene (in torr) is

1 50

2 25

3 37.5

4 53.5

Explanation:

$G i v e n t h a t,$
$V a p o u r p r e s s u r e o f b e n z e n e, P_{B e n z e n e}^{o} = 75 t o r r$
$V a p o u r p r e s s u r e o f t o l u e n e, P_{t o l u e n e}^{^{\circ}} = 22 t o r r$
$M o l a r m a s s o f b e n z e n e = 78 g m o l^{- 1}$
$M o l a r m a s s o f t o l u e n e = 92 g m o l^{- 1}$
$W e i g h t o f b e n z e n e = 78 g$
$W e i g h t o f t o l u e n e = 46 g$
$P_{B e n z e n e} = ?$
$\frac{\begin{array}{l} P_{B e n z e n e}^{o} - P_{B e n z e n e} \end{array}}{P_{B e n z e n e}^{o}} = x_{t o l u e n e}$
$\frac{75 - P_{B e n z e n e}}{75} = \frac{\frac{46}{92}}{\frac{46}{92} + \frac{78}{78}} = \frac{0.5}{1.5} = \frac{1}{3}$
$3 (75 - P_{B e n z e n e}) = 75 \Rightarrow P_{B e n z e n e} = 50 t o r r$

CHXII02:SOLUTIONS

319444 I. n-hexane + n-heptane
II. acetone + ethanol
III. bromoethane + chloroethane
IV. benzene + toluene
Which of the following combination is an example of ideal solutions ?

1 I, II, III

2 II, III, IV

3 I, III, IV

4 I, II, IV

CHXII02:SOLUTIONS

319441 The lubricating action of an oil is more if it possesses:

1 High vapour pressure

2 Low vapour pressure

3 High surface tension

4 High density

CHXII02:SOLUTIONS

319442 For an ideal binary liquid mixture

1

Δ S_{(m i x)} = 0; Δ G_{(m i x)} = 0

2

Δ H_{(m i x)} = 0; Δ S_{(m i x)} < 0

3

Δ V_{(m i x)} = 0; Δ G_{(m i x)} > 0

4

Δ S_{(m i x)} > 0; Δ G_{(m i x)} < 0

Explanation:

For an ideal solution; $Δ H = 0 a n d Δ V = 0$
$F r o m, Δ G = Δ H - T Δ S$
$Δ G = - v e$
Hence, $Δ G < 0 a n d Δ S > 0$

KCET - 2014

CHXII02:SOLUTIONS

319443 Benzene and toluene form nearly ideal solution. At $20^{\circ} C$ , the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at $20^{\circ} C$ for a solution containing 78 g of benzene and 46 g of toluene (in torr) is

1 50

2 25

3 37.5

4 53.5

Explanation:

$G i v e n t h a t,$
$V a p o u r p r e s s u r e o f b e n z e n e, P_{B e n z e n e}^{o} = 75 t o r r$
$V a p o u r p r e s s u r e o f t o l u e n e, P_{t o l u e n e}^{^{\circ}} = 22 t o r r$
$M o l a r m a s s o f b e n z e n e = 78 g m o l^{- 1}$
$M o l a r m a s s o f t o l u e n e = 92 g m o l^{- 1}$
$W e i g h t o f b e n z e n e = 78 g$
$W e i g h t o f t o l u e n e = 46 g$
$P_{B e n z e n e} = ?$
$\frac{\begin{array}{l} P_{B e n z e n e}^{o} - P_{B e n z e n e} \end{array}}{P_{B e n z e n e}^{o}} = x_{t o l u e n e}$
$\frac{75 - P_{B e n z e n e}}{75} = \frac{\frac{46}{92}}{\frac{46}{92} + \frac{78}{78}} = \frac{0.5}{1.5} = \frac{1}{3}$
$3 (75 - P_{B e n z e n e}) = 75 \Rightarrow P_{B e n z e n e} = 50 t o r r$

CHXII02:SOLUTIONS

319444 I. n-hexane + n-heptane
II. acetone + ethanol
III. bromoethane + chloroethane
IV. benzene + toluene
Which of the following combination is an example of ideal solutions ?

1 I, II, III

2 II, III, IV

3 I, III, IV

4 I, II, IV

CHXII02:SOLUTIONS

319441 The lubricating action of an oil is more if it possesses:

1 High vapour pressure

2 Low vapour pressure

3 High surface tension

4 High density

CHXII02:SOLUTIONS

319442 For an ideal binary liquid mixture

1

Δ S_{(m i x)} = 0; Δ G_{(m i x)} = 0

2

Δ H_{(m i x)} = 0; Δ S_{(m i x)} < 0

3

Δ V_{(m i x)} = 0; Δ G_{(m i x)} > 0

4

Δ S_{(m i x)} > 0; Δ G_{(m i x)} < 0

Explanation:

For an ideal solution; $Δ H = 0 a n d Δ V = 0$
$F r o m, Δ G = Δ H - T Δ S$
$Δ G = - v e$
Hence, $Δ G < 0 a n d Δ S > 0$

KCET - 2014

CHXII02:SOLUTIONS

319443 Benzene and toluene form nearly ideal solution. At $20^{\circ} C$ , the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at $20^{\circ} C$ for a solution containing 78 g of benzene and 46 g of toluene (in torr) is

1 50

2 25

3 37.5

4 53.5

Explanation:

$G i v e n t h a t,$
$V a p o u r p r e s s u r e o f b e n z e n e, P_{B e n z e n e}^{o} = 75 t o r r$
$V a p o u r p r e s s u r e o f t o l u e n e, P_{t o l u e n e}^{^{\circ}} = 22 t o r r$
$M o l a r m a s s o f b e n z e n e = 78 g m o l^{- 1}$
$M o l a r m a s s o f t o l u e n e = 92 g m o l^{- 1}$
$W e i g h t o f b e n z e n e = 78 g$
$W e i g h t o f t o l u e n e = 46 g$
$P_{B e n z e n e} = ?$
$\frac{\begin{array}{l} P_{B e n z e n e}^{o} - P_{B e n z e n e} \end{array}}{P_{B e n z e n e}^{o}} = x_{t o l u e n e}$
$\frac{75 - P_{B e n z e n e}}{75} = \frac{\frac{46}{92}}{\frac{46}{92} + \frac{78}{78}} = \frac{0.5}{1.5} = \frac{1}{3}$
$3 (75 - P_{B e n z e n e}) = 75 \Rightarrow P_{B e n z e n e} = 50 t o r r$

CHXII02:SOLUTIONS

319444 I. n-hexane + n-heptane
II. acetone + ethanol
III. bromoethane + chloroethane
IV. benzene + toluene
Which of the following combination is an example of ideal solutions ?

1 I, II, III

2 II, III, IV

3 I, III, IV

4 I, II, IV