JEE Main levelSingle correct optionDifficulty 2 of 3sb091
Assertion (A): Anhydrous MgClX2 cannot be obtained by simply heating MgClX2⋅6HX2O in air.
Reason (R): On heating, the hydrate undergoes hydrolysis and gives Mg(OH)Cl or MgO with loss of HCl.
ABoth A and R are true and R is the correct explanation of A
BBoth A and R are true but R is not the correct explanation of A
CA is true but R is false
DA is false but R is true
Answer: A
Mg2+ is strongly polarising, so on heating the coordinated water hydrolyses the chloride, giving Mg(OH)Cl and finally MgO with HCl. Dehydration must be done in a stream of dry HCl to suppress this. Both statements are true and R explains A.