what is the balanced chemical equation occurring when potassium metal reacts with water to form potassium…

what is the balanced chemical equation occurring when potassium metal reacts with water to form potassium hydroxide and hydrogen gas? 2k(s) + 2h₂o(l) → 2koh(aq) + h₂(g) k(s) + h₂o(l) → k(oh)₂(aq) + h(g) k(s) + 2h₂o(l) → koh(aq) + h₂(g)

what is the balanced chemical equation occurring when potassium metal reacts with water to form potassium hydroxide and hydrogen gas? 2k(s) + 2h₂o(l) → 2koh(aq) + h₂(g) k(s) + h₂o(l) → k(oh)₂(aq) + h(g) k(s) + 2h₂o(l) → koh(aq) + h₂(g)

Answer

Brief Explanations:

To balance the chemical equation for the reaction of potassium (K) with water (H₂O) to form potassium hydroxide (KOH) and hydrogen gas (H₂), we check the number of each atom on both sides:

  1. Potassium (K):

    • Left side: Let's assume the coefficient of K is ( x ). Initially, in the unbalanced equation ( \text{K}(s) + \text{H}_2\text{O}(l) \rightarrow \text{KOH}(aq) + \text{H}_2(g) ), there is 1 K on the left.
    • Right side: In KOH, there is 1 K per formula unit. Let the coefficient of KOH be ( y ). So, for K balance, ( x = y ).

  2. Hydrogen (H):

    • Left side: In H₂O, each molecule has 2 H atoms. If the coefficient of H₂O is ( z ), then total H on left is ( 2z ).
    • Right side: In KOH, each formula unit has 1 H, and in H₂, each molecule has 2 H atoms. So total H on right is ( y + 2w ) (where ( w ) is the coefficient of H₂).
    • For the correct balanced equation ( 2\text{K}(s) + 2\text{H}_2\text{O}(l) \rightarrow 2\text{KOH}(aq) + \text{H}_2(g) ):
      • K: Left = 2, Right = 2 (in 2 KOH) → balanced.
      • O: Left = 2 (in 2 H₂O), Right = 2 (in 2 KOH) → balanced.
      • H: Left = ( 2\times2 = 4 ) (in 2 H₂O), Right = ( 2\times1 + 2\times1 = 4 ) (2 H in 2 KOH and 2 H in H₂) → balanced.

Now let's check the other options:

  • Second option: ( \text{K}(s) + \text{H}_2\text{O}(l) \rightarrow \text{K(OH)}_2(aq) + \text{H}(g) ): Potassium hydroxide is KOH, not K(OH)₂, and H gas is diatomic (H₂), not monoatomic (H). So this is incorrect.
  • Third option: ( \text{K}(s) + 2\text{H}_2\text{O}(l) \rightarrow \text{KOH}(aq) + \text{H}_2(g) ):
    • K: Left = 1, Right = 1 → K balanced.
    • O: Left = 2 (in 2 H₂O), Right = 1 (in KOH) → O not balanced.
    • H: Left = ( 2\times2 = 4 ), Right = ( 1 + 2 = 3 ) → H not balanced. So this is incorrect.
    • Fourth option: Wait, the third option in the list (the last one) is ( \text{K}(s) + 2\text{H}_2\text{O}(l) \rightarrow \text{KOH}(aq) + \text{H}_2(g) ) which we just saw is unbalanced. The first option is balanced as shown above.

Answer:

A. ( 2\text{K}(s) + 2\text{H}_2\text{O}(l) \rightarrow 2\text{KOH}(aq) + \text{H}_2(g) )