Calculate the mass of potassium hydroxide required to completely neutralize the solution, containing 4.9 g of sulfuric acid.

1. Neutralization of sulfuric acid with potassium alkali is described by the reaction equation:

2KOH + H2SO4 = K2SO4 + 2H2O;

2. Calculate the chemical amount of acid to be neutralized:

n (H2SO4) = m (H2SO4): M (H2SO4);

M (H2SO4) = 2 + 32 + 4 * 16 = 98 g / mol;

n (H2SO4) = 4.9: 98 = 0.05 mol;

3. From the ratio of substances in the equation, we determine the amount of reacted hydroxide:

n (KOH) = n (H2SO4) * 2 = 0.05 * 2 = 0.1 mol;

4. Find the mass of potassium hydroxide:

m (KOH) = n (KOH) * M (KOH);

M (KOH) = 39 + 17 = 56 g / mol;

m (KOH) = 0.1 * 56 = 5.6 g.

Answer: 5.6 g.