How'd u answer this!? (1 Viewer)

[mecramarathon]

Aqueous solutions of SO*2 and HCL were prepared and the pH of each solution measured.

Solution of SO*2
Volume of gas at 25 degrees and 100kPa 2.48 L
Volume of solution 1 L
PH 1.43

Solution of HCl
Volume of gas at 25 degrees and 100kPa 0.49
Volume of solution 2 L
pH 2.00

Q: calculate the concentration and the acid strength of each solution.

 

[inedible]

We know how many moles of SO2 are there as at 25 deg and 100kPa there are 24.79L/Mole
N(SO2)=2.48/24.79
=0.1 moles
Since it is dissolved in 1L of water, the concentration is 0.1 mole/L
We can write an equation for SO2 reacting with water
SO2+H2O->H2SO3
and an equation for the ionisation of it in water
H2SO3 +2H2O ->SO3(2-) + 2H3O(+)
1 : 2 : 1 : 2
Take note of the ratio, this means if it completely ionises, it will form 0.2 moles of hydronium ion,
Now, the pH is 1.43, that means there is a concentration of 10^-1.43 hydronium ion, in 1 litre of water, this means there is 0.0371535 moles of hydronium ions
Thus only 0.0371535/0.2 *100 % of H2SO3 ionises
=18.58%
=19%(2 sig. fig.)

Sorry I don't have time to do the second one, but hopefully from my working you can work it out yourself