[mariam amro]

Another question that I don't understand is this...

For a laboratory experiment, a student placed sodium hydroxide crystals on a watch glass, assembled the titration equipment and prepared a solution of 0.10 M sulfuric acid. Then he weighed 4 grams of sodium hydroxide and added it to enough water to make 1 liter of solution. What might be a source of error in the results of the titration?

A) Some sulfuric acid evaporated
B) The sulfuric acid became more concentrated.
C) The NAOH solution gained weight. Thus increasing its molarity.
D) The NaOH crystals gained H2O weight, this making the solution less than 0.1 M.
E) The evaporation of sulfuric acid solution countered the absorption of H2O by the NaOH solution.
The answer is D.


Thanks in advance

[cseil]

You have to show your attempt into solving the problem.
What do you think it's wrong here?

[mariam amro]

Well I don't exactly know what the question means.
But I probably think that the problem doesn't have to do with sulfuric acid evaporating.

[cseil]

See: https://en.wikipedia.org/wiki/Hygroscopy
NaOH is highly hygroscopic.

I suppose that you couldn't get it if you didn't know that.