Final answer:
To find the new concentrations of the buffer components after adding HCl, we calculate the moles of HCl added and adjust the concentrations of HNO₂ and NaNO₂ accordingly. The concentration of HNO₂ will increase, whereas the concentration of NaNO₂ will decrease by the amount of HCl added.
Step-by-step explanation:
The student is asking about the changes in concentration of a buffer solution after the addition of a strong acid, HCl. The buffer is originally composed of HNO₂ (nitrous acid) and NaNO₂ (sodium nitrite). To determine the new concentrations, we must first calculate the moles of HCl added.
Molar mass of HCl = 36.46 g/mol
Moles of HCl = 1.3 g / 36.46 g/mol = 0.0356 mol
The added HCl will react with the NaNO₂ to form HNO₂ and NaCl. Given that the buffer solution volume is fixed at 1.0 L, now ignoring volume changes as the amount of HCl is small compared to the volume of the buffer. Assuming the reaction goes to completion, the number of moles of HNO₂ will increase by the moles of HCl added since they react in a 1:1 ratio.
New concentration of HNO₂ = 0.120 M + 0.0356 mol / 1.0 L = 0.1556 M
New concentration of NaNO₂ = 0.195 M - 0.0356 mol / 1.0 L = 0.1594 M