Answer:
pH = 1.85
Explanation:
The reaction of H₂NNH₂ with HNO₃ is::
H₂NNH₂ + HNO₃ → H₂NNH₃⁺ + NO₃⁻
Moles of H₂NNH₂ and HNO₃ are:
H₂NNH₂: 0.0400L ₓ (0.200mol / L) = 8.00x10⁻³ moles of H₂NNH₂
HNO₃: 0.1000L ₓ (0.100mol / L) = 0.01 moles of HNO₃
As moles of HNO₃ > moles of H₂NNH₂, all H₂NNH₂ will react producing H₂NNH₃⁺, but you will have an excess of HNO₃ (Strong acid).
Moles of HNO₃ in excess are:
0.01 mol - 8.00x10⁻³ moles = 2.00x10⁻³ moles of HNO₃ = moles of H⁺
Total volume is 100.0mL + 40.0mL = 140.0mL = 0.1400L.
Thus, [H⁺] is:
[H⁺] = 2.00x10⁻³ moles / 0.1400L = 0.0143M
As pH = - log [H⁺]
<h3>pH = 1.85 </h3>
