A mixture of two solid elements with a mass of `1.52g` was treated with an excess of hydrochloric acid. `A` volume of `0.896 dm^(3)` of a gas was liberated in this process and `0.56 g` of a residue remained which was undissolved in the excess of the acid.
In another experiment, `1.52 g` of the same mixture were allowed to react with an excess of a `10%` sodium hydroxide solution. In this case `0.896 dm^(3)` of a gas were also evolved but `0.96 g` of an undissolved residue remained.
In the third experiment, `1.52 g` of the initial mixture were heated to high temperature without acess of the air. In this way a compound was formed which was totally soluble in hydrochloric acid and `0.448 dm^(3)` of an unknown gas were released. All the gas obtained was introduced into a one litre closed vessel filled with oxygen. After the reaction of the unknown gas with oxygen the pressure in the vessel decreased by approximately ten times `(T=const)`.
Write chemical equations for the above reactions and prove their correctness by calculations. In solving the problem consider that the volumes of gases were measured at `STP` and round up the relative atomic masses to whole numbers.

Answer

A