KCET 2014 Chemistry Solved Paper

The reactions involved are as follows:
(I) HCl+NH3(aq)→NH4Cl
(III) H2SO4+2NH3(aq)→(NH4)2SO4
Now, according to Henderson Haselbach equation
pH=pKa+log(‌

[A−]

[HA]

)
=14−pKb+log(‌

[A−]

[HA]

)
=9.26+log(‌

[A−]

[HA]

)
Thus, pH depends on the strength of conjugate acid. The order acid strength of the reactants is as follows: CH3COOH<HCl<H2SO4..Also NH3(aq) is a strong base. As conjugate base of weak acid is strongly acidic, we have the acidic strength of products as That is, (II) > (I) > (III).