Solutions · JEE Main previous year questions

2017 2 questions

1. Q802017 · 9 Apr 2017 · Shift 1

   The increasing order of the boiling points for the following compounds is : $$\begin{array}{cccc}{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}& {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}& {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{C}{\mathrm{H}}_3& {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OC}{\mathrm{H}}_3\\ \text{(I)}& \text{(II)}& \text{(III)}& \text{(IV)}\end{array}$$

   1. A.(III) < (IV) < (II) < (I)
   2. B.(IV) < (III) < (I) < (II)
   3. C.(II) < (III) < (IV) < (I)
   4. D.(III) < (II) < (I) < (IV)
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   Answer: A

2. Q652017 · 8 Apr 2017 · Shift 1

   5 g of $\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_4$ was dissolved in x g of ${\mathrm{H}}_2\mathrm{O}$. The change in freezing point was found to be $3.82^{\circ }\mathrm{C}$. If $\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_4$ is 81.5% ionised, the value of x (${\mathrm{K}}_{\mathrm{f}}$ for water=$1.86^{\circ }\mathrm{C}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$) is approximately : (molar mass of $\mathrm{S}=32\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ and that of $\mathrm{Na}=23\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$)

   1. A.$15\mathrm{g}$
   2. B.$25\mathrm{g}$
   3. C.$45\mathrm{g}$
   4. D.$65\mathrm{g}$
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   Answer: C