Question

Non stoichiometric hydrides are produced by:
A) Palladium, Vanadium
B) Manganese, Lithium
C) Nitrogen, Fluorine
D) Carbon, Nickel

Answer 1

Hint:
The hydrides which does not follow the Law of Constant proportion. In the Law of constant proportion the atoms combined in the whole number ratio and fixed composition of atoms.

Complete step by step answer:
Non stoichiometric hydrides are formed by the reaction of Hydrogen molecules and d-block and f-block and do not follow law of constant proportions. The metal and hydrogen are combined in the fractional form. Composition of these hydrides vary with temperature and pressure.
Non stoichiometric hydrides are chemical inorganic compounds and its physical state is solid. These non stoichiometric hydrides are electrically neutral.
So coming to First option Palladium and Vanadium both are d-block elements and have vacant d- orbitals and form compounds with hydrogen in the fractional form.

Second option is Manganese and Lithium, Manganese is d-block element and Lithium is s-block element. So Lithium forms stoichiometric hydrides because Lithium is alkali metal easily loses electrons and hydrogen takes electrons and forms stoichiometric hydride.

Third option is Nitrogen and Fluorine both are p- block elements. Both the atoms form stoichiometric hydrides. Nitrogen combines with Hydrogen and forms Ammonia, Fluorine and Hydrogen combines Hydrofluoric acid.

Fourth option is Carbon and Nickel, Carbon is p-block element and Nickel is d-block element.
So carbon can form stoichiometric hydride. Carbon combines with Hydrogen and forms Methane.
So the second, third and fourth option is that one of the given elements follows the law of constant proportions.
The examples of Palladium non stoichiometric hydrides are $HP{d_{0.03}}\;HP{d_{0.57}}$. Vanadium non stoichiometric hydrides examples $V{H_{0.5}}\;V{H_{0.8}}$
Hence the answer is (A) Palladium, Vanadium.

Note:
Stoichiometric hydrides represent actual formulas but non stoichiometric hydrides represent other than actual formulas which will vary based on temperature and pressure.