$(A)$ $0.01 \,M\, HCl$
$(B)$ $0.01 \,M \,NaOH$
$(C)$ $0.01 \,M \,CH _{3} COONa$
$(D)$ $0.01 \,M \,NaCl$
$(I){\mkern 1mu} C{H_3}CH_2^ - {\mkern 1mu} + {\mkern 1mu} \mathop {C{H_3}N{H_2}}\limits_{p{K_a} = 35} \rightleftharpoons \mathop {C{H_3}C{H_3}}\limits_{p{K_a} = 50} + C{H_3}N{H^ - }$
$(II){\mkern 1mu} {F^ - }{\mkern 1mu} + {\mkern 1mu} \mathop {{H_2}O}\limits_{p{K_a} = 15.7} \rightleftharpoons \mathop {HF}\limits_{p{K_a} = 3.2} + H{O^ - }$