Question

-The correct formula for permanganic acid is:
A.$HMn{O}_4$
B.$KMn{O}_4$
C.$H_{2}Mn{O}_4$
D.$Mn{O}_2$

Answer 1

Hint: Permanganic acid is the conjugate acid of permanganate salts. It is most often prepared by the reaction of dilute sulphuric acid with a solution of barium permanganate, the insoluble barium sulphate byproduct being removed by filtering.

Complete step by step answer:
The permanganic acid is the inorganic compound. Permanganic acid is the strong oxoacid. The correct formula for permanganic acid is $HMn{O}_4$.
So the correct option is A.

Additional Information:-Permanganic acid is a strong oxoacid and it has been isolated as its dihydrate. Crystalline permanganic acid has been prepared at low temperatures as the dihydrate. It is a strong acid. As a strong acid, it is deprotonated to form the intensely purple coloured permanganates. Potassium permanganate is a widely used, versatile and powerful oxidizing agent. Permanganic acid solutions are unstable and gradually decompose into manganese dioxide, oxygen and water, with initially formed manganese dioxide catalyzing further decomposition. Decomposition is accelerated by heat, light and acids. Concentrated solutions decompose more rapidly than dilute. Permanganic acid is assumed to adopt a tetrahedral structure. Permanganic acid has also been prepared through the reaction of hydrofluorosilicic acid with potassium permanganate, through electrolysis and through hydrolysis of manganese heptoxide , though the last route often results in explosions. In the structure of permanganic acid the manganese is attached to three oxygen atoms with double bonds and a single bond with hydroxide.

Note:
The sulphuric acid used must be dilute in reactions where permanganic acid is produced. The reactions of permanganates with concentrated sulphuric acid yield the anhydride, manganese heptoxide.