Equivalent weight of H3PO2 in a reaction is found to be half of its mo...
An equivalent weight of H3PO2 when it disproportionates into PH3 and H3PO3 is
For disproportionation reactions, use a trick to find equivalent mass; E = E1 + E2; where E1 and E2 are equivalent masses of oxidation and reduction half-reactions of the same element.
Now, find the n-factor(total change in oxidation number per molecule) and then equivalent mass = molar mass/n-factor.
So, when H3PO2 changes into PH3, the oxidation state of phosphorous changes from +1 to -3 so as n-factor is 4. Also when H3PO2 changes into H3PO3, the oxidation state of phosphorous changes from +1 to +5 so as n-factor is again 4.
Now equivalent mass of H3PO2, E =(M/4) + (M/4) = M/2
Hence, the correct option is b.
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Equivalent weight of H3PO2 in a reaction is found to be half of its mo...
Explanation:
The equivalent weight of a substance is defined as the molecular weight divided by the number of equivalents of the substance involved in a chemical reaction. In this case, the equivalent weight of H3PO2 is found to be half of its molecular weight. Let's analyze the given options to understand why this is the case.
Option A: Reaction of two H+ ions
H3PO2 does not contain any H+ ions. It consists of phosphorus, hydrogen, and oxygen atoms. Therefore, option A is not the correct answer.
Option B: Oxidation of H3PO3
H3PO2 can be formed by the oxidation of H3PO3. This oxidation reaction involves the conversion of one molecule of H3PO3 to one molecule of H3PO2, resulting in the removal of one oxygen atom. The molecular weight of H3PO2 is half of the molecular weight of H3PO3. Therefore, option B is the correct answer.
Option C: Oxidation of H3PO4
H3PO2 is not formed by the oxidation of H3PO4. The oxidation of H3PO4 results in the formation of phosphoric acid (H3PO4), not phosphorous acid (H3PO2). Therefore, option C is not the correct answer.
Option D: Reduction of PH3
H3PO2 is not formed by the reduction of PH3. The reduction of PH3 would result in the formation of phosphine (PH3), not phosphorous acid (H3PO2). Therefore, option D is not the correct answer.
Conclusion:
Based on the analysis, we can conclude that the correct answer is option B: Oxidation of H3PO3. The equivalent weight of H3PO2 is found to be half of its molecular weight because it is formed by the oxidation of H3PO3, resulting in the removal of one oxygen atom.
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