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Amol took 10 mL of 2.2 times 10-5 M hydrochloric acid solution. He then diluted it to 1 litre. He found that the pH of diluted solution is a) 4.7b) 6.7 c) 4.5 d) 6.5 |
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Answer» Answer is : d) 6.5 Correct option is (D) 6.5 using molarity equation- M1V2 = M2V2 10 ml x 2.2 x 10-5 M = 1000 mL x M2 M2 = 2.2 x 10-7M of HCl \(\therefore\) final concentration of HCl = 2.2 x 10-7 M. Here, we also consider the H+ions come from water dessociation. We know that [H+] = [\(\bar O\)H] = 1 x 10-7 \(\therefore\) Total H+ concentration in solution = (2.2 x 10-7) + (1 x 10-7) M = 3.2 x 10-7 M \(\therefore\) PH of solution = - log[H+] = -[log(3.2) + log 10-7] = -0.5 + 7 = 6.5 Hence, the PH of final solution will be 6.5 |
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