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JAMB Chemistry 2024 Paper

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Question : 18

Total: 138

127g of sodium chloride was dissolved in 1.0dm

^{3}

of distilled water at 25

^{0}

C . Determine the solubility in moldm

^{-3}

of sodium chloride at that temperature. [Na = 23, Cl = 35.5]

1.0
2.0
2.2
4.1

Solution:

Concept:

Solubility in

\text{moldm}^{-3}

is the amount of solute dissolved in

1.0\text{ dm}^3

of solution.

Explanation:

Molar mass of

\mathrm{NaCl}

is

23 + 35.5 = 58.5\text{ gmol}^{-1}

.

Moles of

\mathrm{NaCl}

dissolved

= \frac{127}{58.5} = 2.17\text{ mol}

.

This amount is dissolved in

1.0\text{ dm}^3

, so solubility

= \frac{2.17\text{ mol}}{1.0\text{ dm}^3}

.

Therefore, solubility

= 2.17 \approx 2.2\text{ moldm}^{-3}

.

Answer:

2.2\text{ moldm}^{-3}

Option C.

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