A student has 100mL of 0.1 M KCl solution. To make it 0.2 M, he has to

V1=100ml   ;   V2=?M1=0.1M     ;    M2=0.2MV1M1=V2M2100 X 0.1=  V2 X 0.2V2=50mlBy evoparating 50ml of solution, M becoms 0.2M (If volume is halved then M is doubled)Assuming volume of solution remains unchangedBy adding 0.01 moles of KCl, M increases to 0.2M