Question

Butter of tin is:
(A) $\text{SnC}{{\text{l}}_{\text{2}}}\text{.5}{{\text{H}}_{\text{2}}}\text{O}$
(B) $\text{SnC}{{\text{l}}_{\text{2}}}\text{.2}{{\text{H}}_{\text{2}}}\text{O}$
(C) $\text{SnC}{{\text{l}}_{4}}\text{.4}{{\text{H}}_{\text{2}}}\text{O}$
(D) $\text{SnC}{{\text{l}}_{4}}\text{.5}{{\text{H}}_{\text{2}}}\text{O}$

Answer 1

Due to the softness of the compound, stannic chloride is also called Butter of tin and it is a colourless liquid that fumes in contact with air. It is often used as the precursor to form other tin compounds.

Complete step by step answer
Stannic chloride is prepared by the reaction of tin with chlorine gas at 115 $^{\text{0}}\text{C}$ . Anhydrous Tin (IV) chloride solidifies at -33 $^{\text{0}}\text{C}$ to form monoclinic crystals of the compound. There are several hydrates of Tin (IV) chloride or stannic chloride among which the pentahydrate is known as “Butter of tin”, formerly.
All these compounds consist of varying amounts of $\left[ \text{SnC}{{\text{l}}_{4}}\text{.}{{\left( {{\text{H}}_{\text{2}}}\text{O} \right)}_{2}} \right]$ together with varying amounts of water of crystallization. The additional water leave the link the molecules of $\left[ \text{SnC}{{\text{l}}_{4}}\text{.}{{\left( {{\text{H}}_{\text{2}}}\text{O} \right)}_{2}} \right]$ through hydrogen bonding. Although the pentahydrate is the most common hydrate there are other hydrates that have been identified.
Besides water, other Lewis bases form adducts with stannic chloride as well, these include ammonia and organophosphines.
Hence, the correct option is D.

Note
Although a specialized application, $\text{SnC}{{\text{l}}_{4}}$ is used in the Friedel Crafts synthesis as a Lewis acid alkylation and cyclization reaction. Stannic chloride is used in organic reactions with 90% nitric acid and the selective nitration of activated aromatic rings in the presence of the inactive ones. The main application of the stannic chloride is as a precursor in the organotin compounds which are applied as catalyst stabilizers and as polymer stabilizers.