20ml of 0.1M H2SO4 solution is added to 30ml of 0.2M NH4OH solution. The pH of resultant mixture is ( pkb of NH4OH = 4.7 )

SA            +    WB             →             Salt   +   Water 40-40 meq    60-40meq                40meq pOH=4.7+ logsaltbase; pOH=4.7+ log 4020; pOH= 5 ; pH=9 ;