equivalent weight

hey guys could anyone explain how to find equvalent weight in reaction such as,

example 1-

4KMnO₄ + 5HC₂O₄.H₂C₂O₄.2H₂O + 13H₂SO₄ â†’ 4MnSO₄ + 9KHSO₄ +20CO₂ + 18H₂O

the equivalent weight of potassium tetraoxalate crystals are?
a-84.76
b-63.5
c-127
d-158.75

answer given is option b

example 2-

find the equivalent weight of K₂Cr₂O₇ (molecular weight=M)

reaction

K₂Cr₂O₇ + HCl â†’ KCl + CrCl₃ + Cl₂ + H₂O

my question is why do we need to balance the reactions only in some reactions to find the equivalent weight .

Regards,
gp

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