61. What is equivalent mass? Why can you state positively the equivalent mass of LiOH but not of H,SO,? 62. Explain why the number of equivalents in a mole of acicd or base is not always the same. 63. State the number of equivalents in 1 mole of HNO, in H\' + HSeo. 1 mole of H SeO4 in the reaction H Se04 (Se is selenium, Z = 34.)
Solution
61 - Equivalent mass of a substance is defined as the weight in grams required for that substance to react with 1 mole hydrogen. Mathematically given as atomic weight / valency. It is possible to state equivalent mass of LiOH because it will break in lithium cation and hydroxide anion in one way but H2SO4 can dissociate by giving one or two protons. So depending upon dissociation reaction and valency involved only we can state it\'s equivalent mass.
62 - The number of equivalent in a mole of acid or base is not always same because it is not always fixed that how many protons will the acid donate or how many protons will a base accept in a reaction.
H2SO4 ----> HSO4- + H+
H2SO4 -----> SO4-- + 2H+
So, both can happen so not always same.
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A Critique of the Proposed National Education Policy Reform
61- What is equivalent mass- Why can you state positively the equivale.docx
1. 61. What is equivalent mass? Why can you state positively the equivalent mass of LiOH but not
of H,SO,? 62. Explain why the number of equivalents in a mole of acicd or base is not always the
same. 63. State the number of equivalents in 1 mole of HNO, in H' + HSeo. 1 mole of H SeO4
in the reaction H Se04 (Se is selenium, Z = 34.)
Solution
61 - Equivalent mass of a substance is defined as the weight in grams required for that substance
to react with 1 mole hydrogen. Mathematically given as atomic weight / valency. It is possible to
state equivalent mass of LiOH because it will break in lithium cation and hydroxide anion in one
way but H2SO4 can dissociate by giving one or two protons. So depending upon dissociation
reaction and valency involved only we can state it's equivalent mass.
62 - The number of equivalent in a mole of acid or base is not always same because it is not
always fixed that how many protons will the acid donate or how many protons will a base accept
in a reaction.
H2SO4 ----> HSO4- + H+
H2SO4 -----> SO4-- + 2H+
So, both can happen so not always same.
