The volumes of 1M HCl and 5M HCl to be mixed to get 2 lit of 2M HCl are

Total volume of the mixture = 2l , Molarity of the mixture = 2M  sample(I)                    sample (II)V1 = xlit                       V2 = (2-x) litM1 = 1M                       M2 = 5MResultant Molarity , M=V1M1+V2M2V1+V2 2 =x(1)+(2-x)524=x+10_5x                      4x=6                          x=1.5l                     volume of 1M HCl required = 1.5l    volume of 5M HCl required  = (2-1.5)l = 0.5l