Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

231. Urea forms an ideal solution in water. Determine the vapour pressure of an aqueous solution contains 10% by mass of urea at 40⁰C. (Vapour pressure of water at 40⁰C = 55.3 mm of Hg)

Answer:

$\frac{p ° - p}{p °}$ = x_urea

Let the mass of solution be 100g
therefore mass of urea = 10 g
molecular mass of urea = 60 g

x_urea = 10/60 =1/6

molecular mass of water = 18g
x_water = 90/18 =5

$x_{urea} = \frac{mole fraction of urea}{total mole fraction of solution} x_{urea} = \frac{1 / 6}{1 / 6 + 5} = \frac{1 / 6}{31 / 6} x_{urea} = 1 / 31 using above formula \frac{55.3 - p}{55.3} = \frac{1}{31} 55.3 - p = \frac{55.3}{31} p = 55.3 - \frac{55.3}{31} 55.3 (1 - \frac{1}{31}) = p p = 55.3 \times \frac{30}{31} p = 53.52 mm Hg$

151 Views

232. A solution is made by dissolving 30 g of a non-volatile solute in 90g of water. It has a vapour pressure of 2.8 kPa at 298 K. At 298 K, vapour pressure of pure water is 3.64 kPa. Calculate the molar mass of the solute.

619 Views

233. At 300 K, 36 g of glucose present per litre in its solution has an osmotic pressure of 4.98 bar. If osmotic pressure of solution is 1.52 bar at the same temperature, what would be its concentration.

222 Views

234.

Calculate the vapour- pressure lowering of water when5.67g of glucose, C₆H₁₂O₆ is dissolved in 25.2 g water at 25⁰C. The vapour pressure of water at 25⁰C is 23.8 mmHg. What is the vapour pressure of the solution?

172 Views

235. A 4% solution of sucrose is isotonic with 3% solution of an unknown organic substance. Calculate the molecular mass of unknown resistance.

273 Views

236. Calculate molarity and molality of 13% solution (by weight of sulphuric acid. Its density is 1.020 g cm^–3. (At. mass, H = 1,16, S = 32 amu).

724 Views

237.

What will be the boiling point of bromine when 87.25 x 10^-3 g of Sulphur is added to 39g of bromine? Bromine boils at 332.15K [K_bfor Br₂ -5.2K kgmole^-1]

175 Views

238.

The freezing point of a solution containing 0.2g of acetic acid in 20.0 g of benzene is lowered by 0.45⁰C. calculate the degree of association of acetic acid in benzene. (K_f for benzene =5.12K kg mol-1)

177 Views

239.

Calculate the amount of ice that will separate out on cooling a solution containing 50g of ethylene glycol in 200g water -9.3⁰C (K_f for water =1.86K kf mol^-1).

466 Views