The molarity of a solution obtained by mixing 800 mL of 0.5 M HCl with 200 mL of 1M HCl will be

When two solutions which are obtained by the mixing the different concentration of the same solution is calculated as follows, 1 1 2 2 mixture 1 2 V M V M M = V V x x Here, 1 1 2 2 M = 0.5 M , V = 800 mL M = 1 M , V = 200 mL We have, mixture mixture mixture mixture 800 0.5 200 1 M = 800 200 400 200 M = 1000 600 M = 1000 M = 0.6 M x x >> >> Therefore, the molarity of the mixture is equal to 0.6 M . Thus, (b) is the correct option.