Chemistry Questions on pH and [H+]?

The questions are:

a. 1.75 L of a 37.5% (by mass) solution (d=1.00g/mol) of HCl. What is the pH of .175 L of the same solution?

b. A solution made up of 22 grams of HBr dissolved in enough water to make 479 mL of solution. What is the pH if the same mass of HBr is dissolved in enougn water to make 47.9 mL of solution?

Please show/explain all your work that you performed to get the answer you got. Thank You.

Chemistry Questions on pH and [H+]?imax theater

(a)

1 litre of 37.5% HCl with a density of 1 g/ml (I assume you mean 1 g/ml and not 1 g/mol) is 10.3 M

Calc 1000 ml x 1 g/ml x 37.5 /100 / 36.5 = 10.3 mol/l

pH is independent of volume of measurement (are you sure you worded your question correctly) so the pH of 1.75 L is the same 0.175 L

pH =-log(10.3) = approx -1

pH calculation for a strong acid solution like this will not be as above because hydrogen ion activity is assumed to be 1.0 In strong solution it will be very much different to 1.0 and such pH will be higher.

(b) Without calculating the pH of your HBr solution, the pH will be (ideally) one unit higher id you make the solution 10 times stronger. See the comment above for HCl regarding the real world.

Chemistry Questions on pH and [H+]?

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