Multiple choice

10 g of a sample of Ca(OH)2 is dissolved in 10 ml of 0.5 N HCl solution. The excess of HCl was titrated with 0.2 N NaOH. The volume of NaOH used was 20 cc. Calculate the percentage of Ca(OH)2 in the sample.

  1. 11%

  2. 12%

  3. 1.11%

  4. 2.22%

  5. 99%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Milli eq. of HCl initially = 10 * 0.5 = 5. Milli eq. of NaOH consumed = milli eq. of HCl in excess     = 10 * 0.2 = 2 Therefore, milli eq. of HCl consumed = Millie q. of Ca(OH)2     = 5 – 2 =3 Therefore, eq. of Ca(OH)2 = (3 / 1000) = 3 * 10^–3 Mass of Ca(OH)2 = (3 * 10^–3) * (74 / 2) = 0.111 g% Ba(OH)2 = (0.111 / 10) * 100 = 1.11%; which is the required solution of the given problem. Hence, this is the correct option.

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