Question

Which is/are INCORRECT statement?

A) Equivalent weight of H2PO3− is 40.5
B) Eq. wt. of H2PO4− may be equal to molar mass or less than molar mass depend on reaction.
C) KMnO4 has maximum eq. wt. in acidic medium
D) Oxidation state of H in MgH2 is greater than in H2O2​

Answer 1

Answer:

option d is incorrect......

Answer 2

Answer:

Options (A), (C), and (D) are incorrect.

Explanation:

The valence factor (n-factor) of a compound depends upon the reaction in which it is participating.

For example, if we have 1 mole of $H_2SO_4$ reacting with only 1 mole of $NaOH$, the reaction would proceed as:

$H_{2}SO_{4}+NaOH{\longrightarrow}NaHSO4+H_{2}O$

Here, the valence factor of $H_2SO_4$ is 1, as only one mole of hydrogen atoms are displaced when it reacted with one mole of $NaOH$.

If the same quantity of the acid were reacted with 2 moles of the same base, then the valence factor would be 2, as 2 moles of hydrogen atoms would be displaced.

Option A is incorrect as we are not given the reaction in which $H_2PO_3^-$ is participating.

Option B is correct as the equivalent weight of $H_2PO_4^-$ would be equal to its molar mass if its valence factor is 1, and less than its molar mass if its valence factor is greater than 1 which solely depends on the reaction.

Option C is incorrect as the equivalent weight of $KMnO_4$ is maximum in basic medium, and;

Option D is incorrect as the oxidation state of $H$ in $MgH_2$ (-1) is less than that of $H_2O_2$ (+1).