Chemistry Class 11 NCERT Solutions: Chapter 7 Equilibrium Part 27

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Chemistry Class 11 NCERT Solutions Chapter 7 Equilibrium Part 27

Q: 68. The solubility product constant of and are respectively. Calculate the ratio of the molarities of their saturated solutions.

Answer:

Let s be the solubility of

Then,

Let be the solubility of

Therefore, the ratio of the molarities of their saturated solution is

Q: 69. Equal volumes of 0.002 M solutions of sodium iodate and cupric chlorate are mixed together. Will it lead to precipitation of copper iodate? (For cupric iodate

Answer:

When equal volumes of sodium iodate and cupric chlorate solutions are mixed together, then the molar concentrations of both solutions are reduced to half i.e., 0.001 M. Then,

Now, the solubility equilibrium for copper iodate can be written as:

Ionic product of copper iodate:

Since the ionic product is less than ), precipitation will not occur.

Q: 70. The ionization constant of benzoic acid is and for silver benzoate is How many times is silver benzoate more soluble in a buffer of compared to its solubility in pure water?

Answer:

Since

Let the solubility of be x mol/L.

Then,

Thus, the solubility of silver benzoate in a pH 3.19 solution is 1.66 × 10–6 mol/L. Now, let the solubility of C6H5COOAg be x’mol/L.

Then,

Hence, is approximately 3.317 times more soluble in a low pH solution.