Solutions · JEE Main previous year questions

2010 2 questions

1. Q732010 · 25 Apr 2010 · Shift 1

   If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water ($\Delta {\mathrm{T}}_f$), when 0.01 mol of sodium sulphate is dissolved in 1 kg of water, is (${\mathrm{K}}_f=1.86\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$)

   1. A.0.0372 K
   2. B.0.0558 K
   3. C.0.0744 K
   4. D.0.0186 K
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   Answer: B

2. Q742010 · 25 Apr 2010 · Shift 1

   On mixing, heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components (heptane and octane) are 105 kPa and 45 kPa respectively. Vapour pressure of the solution obtained by mixing 25.0g of heptane and 35 g of octane will be (molar mass of heptane = $100\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ and of octane = $114\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$)

   1. A.72.0 kPa
   2. B.36.1 kPa
   3. C.96.2 kPa
   4. D.144.5 kPa
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   Answer: A