Physical Chemistry MCQ with Answers

Physical Chemistry MCQ with Answers

106) To 500 cc of water, 3 x 10⁻³ kg of acetic acid is added. If 23% of acetic acid is dissociated, what will be the depression in freezing point? K_f and density of water are 1.86 K⁄kg and 0.0997 gm⁄cc respectively.

Answer is:

0.228 K

Explanation:

ΔT_f = iK_fm

107) A 0.1M solution of K₂SO₄ is dissolved to the extent of 90%. What would be its osmotic pressure at 27^oC?

Answer is:

6.896 atm

Explanation:

π = iCRT

108) What is the value of i (Van′t Hoff factor) for phosphorus?

Answer is:

0.25

Explanation:

i = observed moles⁄theoretical moles

109) A current of dry air was passed through a solution of 12.5 gm of B in 100 gm of water and then through water alone. The loss in the weight of water was 0.05 gm and that of solution was 1.25 gm. The molecular weight of B is:

Answer is:

56.25 gm⁄mol

110) How much of NaCl should be dissolved in 900 gm of H₂O so that its vapour pressure at 100^oC becomes 380 torr?

Answer is:

25 moles

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