We know that, I Faraday charge liberates 1 eq. of substance. eq. wt. of AI= eq. wt wt.of Al=94.5=0.5 no. of Faraday required =0.5 no. of eq. of H2 produce =0.5 eq. Volume occupied by 1 eq. of H2= 222.4=11.2 Volume occupied by 0.5eq=11.2× 0.5 =5.6 litre at STP