Number of moles of water (n) = $\frac{36}{18}$ = 2

No. of moles of ethyl alcohol (N) = $\frac{828}{46}$ = 18

$\therefore$ Mole-fraction of water = $\frac{\mathrm{n}}{\mathrm{n}+ \mathrm{N}}$ 

= $\frac{2}{2 + 18}$ = $\frac{2}{20}$ = 0.1

PCl₅  $\rightleftharpoons$  PCl₃ + Cl₂

a            0        0

(a-x)      0.2      0.2(in equil)

0.1 mol  mol      mol

Hence, K_c = $\frac{\left[{\mathrm{PCl}}_3\right]\left[{\mathrm{Cl}}_2\right]}{\left[{\mathrm{PCl}}_5\right]}$ = $\frac{\left({\displaystyle \frac{0.2}{10}}\right)\times \left({\displaystyle \frac{0.2}{10}}\right)}{\left({\displaystyle \frac{0.1}{10}}\right)}$

= 0.04

The conjugate acid of water is H₃O⁺

Maleic anhydride is obtained by the oxidation of benzene in the presence of V₂O₅ at 450°C .

2C₆H₆ + 9O₂ $\underset{450°\mathrm{C}}{\overset{{\mathrm{V}}_2{\mathrm{O}}_5}{\to }}$ ( maleic anhydride) + 4H₂O +CO₂

Poisonous gas 'Lewisite' is obtained by the reaction of AsCl₃ with acetylene

CH$\equiv$CH + AsCl₃ $\to$ $\underset{\mathrm{Lewisite}}{\mathrm{CHCl}=\mathrm{CH}-{\mathrm{AsCl}}_2}$

Chlorine is more electronegative (electronegativity = 3.0) than hydrogen (2.1). Hence, hydrogen is electropositive in respect to chlorine.

Fluorine is the most electronegative element of the periodic table. Its electronegativity is 4.0.

Propene reacts with N-bromo succinimide to give allyl bromide , as the allyl hydrogen is comparitively easier to be replaced than vinyl hydrogen .

Phenolphthalein indicator is suitable for the titration of strong base vs. strong acid and strong base vs. weak acid. Here, NaOH, KOH are strong bases and K₂CO₃ also give strong base (KOH) in solution. Hence, phenolphthalien is suitable for each titration.

C₂H₄ + H₂ $\rightleftharpoons$ C₂H₆ + 32.7 Kcal

In this reaction, volume is decreasing and heat is evolving. Hence, according to Le-Chatelier principle, we have to increase pressure, decrease temperature and increase concentration of H₂ to make the reaction proceed in forward direction.