Balance the half reactions

Question

S2O8^2−(aq)→2SO4^2−(aq)

Cr2O7^2−(aq)→Cr^3+(aq)

NO(g)--->NO3. ^-

Answer 1

S₂O₈^2-(aq) ==> SO₄^2-

S₂O₈^2-(aq) ==> 2SO₄^2- ... to balance the S atoms

S₂O₈^2-(aq) ==> 2SO₄^2- + 4H₂O ... to balance the O atoms

S₂O₈^2-(aq) + 8H⁺ ==> 2SO₄^2- + 4H₂O ... to balance the H atoms

S₂O₈^2-(aq) + 8H⁺+ 10e- ==> 2SO₄^2- + 4H₂O ... to balance the charge & this is the balanced half reaction

Cr₂O₇^2- ==> Cr³⁺

Cr₂O₇^2- ==> 2Cr³⁺ .. to balance Cr atoms

Cr₂O₇^2- ==> 2Cr³⁺ + 7H₂O .. to balance O atoms

Cr₂O₇^2- + 14H⁺ ==> 2Cr³⁺ + 7H₂O .. to balance H atoms

Cr₂O₇^2- + 14H⁺ + 6e- ==> 2Cr³⁺ + 7H₂O .. to balance charge & this is the balanced half reaction

Do the last one the same way. Good luck.