A solution of 100.0 mL of 0.200 M KOH is mixed with a solution of 200.0 mL of 0.150 M NiSO4. (a) Write the balanced chemical equation for the reaction that occurs. (Use the lowest possible coefficients. Include states-of-matter under SATP conditions in your answer.)

2KOH(aq) + NiSO₂(aq) → K₂SO₄(aq) + NiOH₂(s)

Explanation:

This reaction is an example of a double-replacement reaction where the cations of two compounds exchange with its anions. In the reaction:

KOH(aq) + NiSO₄(aq)

There are produced K₂SO₄ and NiOH₂ salts (The last one is insoluble, its state is (s) but K₂SO₄ is very soluble, its state is (aq). The unbalanced reaction is:

KOH(aq) + NiSO₄(aq) → K₂SO₄(aq) + NiOH₂(s)

To balance the potassiums:

And now, the reaction is balanced