Answer:
no one additions exceed the capacity of the buffer
Explanation:
given
Volume buffer = 500.0 mL = 0.5 L
mol HNO₂ = 0.5 L × 0.100 mol/L = 0.05 mol HNO₂
mol NO₂⁻ = 0.5 L × 0.150 mol/L = 0.075 mol NO₂⁻
solution
we know when any base more than 0.05 (HNO2) than exceed buffer capacity
and when any base more than 0.075 (KNO2) than exceed buffer capacity
when we add 250 mg NaOH (0.250 g)
than molar mass NaOH =40 g/mol
and mol NaOH = 0.250 g ÷ 40g/mol
mol NaOH = 0.00625 mol
0.00625 mol NaOH will be neutralized by 0.00625 mol HNO₂
so it would not exceed the capacity of the buffer.
and
when we add 350 mg KOH (0.350 g)
than molar mass KOH =56.10 g
and mol KOH = 0.350 g ÷ 56.10 g/mol
mol KOH = 0.0062 mol
here also capacity of the buffer will not be exceeded
and
now we add 1.25 g HBr
than molar mass HBr = 80.91 g/mol
and mol HBr = 1.25 g ÷ 80.91 g/mol
mol HBr = 0.015 mol
0.015 mol Hbr will neutralize 0.015 mol NO₂⁻
so the capacity will not be exceeded.
and
we add 1.35 g HI
molar mass HI = 127.91 g/mol
so mol HI = 1.35 g ÷ 127.91 g/mol
mol HI = 0.011 mol
capacity of the buffer will not be exceed
