Question

By which of the following tests can we differentiate lead chloride by its groupmates (chlorides of silver and mercury) when present in the same solution?
(A) Lead chloride is tested by its flame colour
(B) On reaction with concentrated sulphuric acid lead chloride gives chlorine gas
(C) Lead chloride is soluble in hot water
(D) It cannot be differentiated separately

Answer 1

Hint: Lead chloride is an inorganic compound which is a white solid under normal conditions. It is poorly soluble in cold water and solubility increases with temperature of the water. Lead chloride is one of the most important lead-based reagents.

Complete step by step solution
Lead chloride in solid state is coordinated by nine chloride ions in tricapped triangular prism formation. Lead chloride forms a white orthorhombic needle.
In the gas phase, lead chloride molecules have a bent structure Cl-Pb-Cl of angle being 98 degree. Lead chloride is sparingly soluble in cold water, but it is soluble in hot water.
Silver chloride is a chemical compound with formula AgCl. Silver chloride is a white crystalline solid which is insoluble or sparingly soluble in cold or hot water. On heating or illuminating silver chloride it converts to silver and chlorine, which is signaled by grey to black or purplish coloration of sample.
Mercury chloride or mercuric chloride is a chemical compound with white crystalline solid and is a laboratory reagent. Mercury chloride is very toxic to humans. Mercury chloride is soluble in cold water but not in warm or hot water.
So, to differentiate lead chloride from other chlorides we need to find that property of lead chloride which is not shown by other chlorides of that group. Therefore, we can say that only lead chloride is soluble in hot water and while other chlorides are not.
Hence the correct answer is option C.

Note:
Uses of lead chloride are as follows,
-Used in production of infrared transmitting glass.
-It is used in the production of ornamental glass or aurene glass.