Acid and Base calculation

Question

When sodium hydrogen sulfate is dissolved in water,the Hso4 ion behaves as a weak acid. If 100g of sodium hydrogen sulfate is dissolved to make a 1.00l solution what will the concentration of hydrogen ions be? Use 1.0 * times 10^-2 as the Ka value and assume complete ionization of the sodium hydrogen sulfate salt.

 

 

please help

Answer 1

1. Find the  number of moles of 100 g of NaHSO₄.  Divide 100g by the molar mass of NaHSO₄.    n = ?

2. Find concentration of NaHSO₄.   Concentration = mole/ liters.    M = n/V = ?

3. Balance the chemical equation.

NaHSO4(aq.) ↔ Na⁺(aq) + HSO₄ ^-(aq)

                                          HSO₄ ^-(aq) ---> H ⁺(aq) + SO₄ ^2-(aq) 

Concentration of NaHSO₄ = concentration of HSO₄ ^- ions for complete ionization.

4. Let x = concentration of H⁺ ions  = concentration of SO₄ ^2- ions

Use the equation for the equilibrium constant

 

Ka = [H⁺]*[SO₄^2-]/[HSO₄^-] =  x.x/M

x^₂ = M.K_a

5. Solve for x