Question

$KF$combines with $HF$ to form $KH{{F}_{2}}$ . The compound contains the species:
A. ${{K}^{+}},{{F}^{-}}$ and ${{H}^{+}}$
B. ${{K}^{+}},{{F}^{-}}$and $HF$
C. ${{K}^{+}}$ and ${{\left[ H{{F}_{2}} \right]}^{-}}$
D. ${{\left[ KHF \right]}^{+}}$ and ${{F}_{2}}$

Answer 1

Potassium hydride is defined as the inorganic compound which have chemical formula $KH$ . It consists of hydrogen and potassium. It is a white solid alkali metal hydride which is used as a strong base for organic synthesis. This compound is dangerously reactive.

Complete step-by-step answer: Potassium hydride can be prepared by the combination of metal and hydrogen. Potassium hydride is not soluble in organic solvents.
Hydrogen fluoride is a chemical compound which has a chemical formula $HF$ . It is a very important feedstock for the preparation of compounds such as pharmaceuticals and polymers. It is used as a component in superacids and it is also used in petrochemical industry.
Potassium bifluoride which has a chemical formula $KH{{F}_{2}}$. It is an inorganic compound which consists of potassium cation and bifluoride anion. The thermal decomposition of potassium bifluoride gives hydrogen fluoride. It is used for the industrial production of fluorine by electrolysis of potassium bifluoride.
Let us see the species that potassium bifluoride contains-
$KH{{F}_{2}}\to {{K}^{+}}+HF_{2}^{-}$
Therefore $KH{{F}_{2}}$consist of ${{K}^{+}}$ and $HF_{2}^{-}$ . The hydrogen bonding between the fluoride ion and hydrogen fluoride results in the formation of $HF_{2}^{-}$.

Hence, the correct is C.

Note: Cations are defined as positively charged ions that are formed by loss of electrons from the metal. Anions are defined as negatively charged ions that are formed by gain of electrons from the non metal.
The formation of hydrogen bonds is known as hydrogen bonding. When a negative end of one molecule attracts the positive end of another, it results in the formation of hydrogen bonds.