Which of the following equations is correctly balanced for the reaction between potassium hydroxide and phosphoric acid to produce potassium phosphate and water?
Show the answer and explanation
Correct answer
B. 3KOH + H3PO4 → K3PO4 + 3H2O
Principle or equation
Balancing chemical equations requires equal numbers of each atom on both sides. For acid-base reactions, the products are salt and water; coefficients must satisfy atom conservation.
Why this answer is correct
Start with KOH + H3PO4 → K3PO4 + H2O. Balance K: need 3 K on left, so 3KOH. Balance PO4: already 1 on each side. Balance H: left has 3 from H3PO4 plus 3 from 3KOH = 6 H; right has 2 H in H2O, so need 3 H2O. Balance O: left has 3 from KOH plus 4 from H3PO4 = 7 O; right has 4 in K3PO4 plus 3 in 3H2O = 7 O. All atoms balanced: 3KOH + H3PO4 → K3PO4 + 3H2O.
Example
For NaOH + H2SO4 → Na2SO4 + H2O, balance: 2NaOH + H2SO4 → Na2SO4 + 2H2O.
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