Environmental Chemistry Questions and Answers

Answer: C

It is Henry's law.

Henry's law states that at constant temperature the amount of a gas dissolved in a liquid is proportional to the partial pressure of that gas above the liquid:

\[ C = k_{H}\, p \]

It explains why opening a soda releases dissolved CO₂ and governs oxygen transfer in aeration tanks. Lambert's law and Beer's law relate the absorption of light to path length and concentration, the basis of spectrophotometry. Rutherford's name belongs to atomic structure and scattering, not to gas solubility.

Answer: D

The correct order is NaCl \(\gt\) LiF \(\gt\) Ca(OH)\(_{2}\) \(\gt\) CaF\(_{2}\), comparing solubilities in moles per litre.

Approximate solubilities at room temperature:

• NaCl: about 360 g/l, roughly 6 mol/l.
• LiF: about 1.3 g/l, roughly 0.05 mol/l.
• Ca(OH)₂: about 1.7 g/l, roughly 0.023 mol/l.
• CaF₂: about 0.016 g/l, roughly 0.0002 mol/l.

Common salt is very soluble and calcium fluoride (fluorite) almost insoluble, which fixes the two ends and rules out options A and C. Between the middle pair, LiF dissolves to about twice the molar concentration of Ca(OH)₂, because its formula mass is far smaller, so option B has those two the wrong way round.