A student adds 1.00x10^-8 moles HCl to a liter of soln. The resulting soln will be acid, basic, neutral, or impossible to determine?

Question

I believe that it is impossible to determine, because it does specify that the temperature was at 25*C.

Which of the species act as a Lewis acid: CH3CH2N or NO2?

I think NO2, because one of its oxygen is missing an electron.

Lactic acid partially dissociates, Ka=1.4x10^-4, to form hydronium ions and conjugate base. Determine kb for this base.

kb=10^-14/ (1.4x10^-4)= 7.1x10^-11
Is that how I am supposed to do this?

Thanks for the help!

Answer 1

A student adds 1.00x10^-8 moles HCl to a liter of soln. The resulting soln will be acid, basic, neutral, or impossible to determine?
A bad question BECAUSE there are no limits on it. Of course it can be determined. We can measure it with a pH meter, for example. Or we can calculate it. Or from common sense, if we have some water that is neutral, and we add some HCl to it (no matter how few molecules of HCl we add), then the resulting solution MUST be acid. Not very acid, perhaps, but acid.

I believe that it is impossible to determine, because it does specify that the temperature was at 25*C.

Which of the species act as a Lewis acid: CH3CH2N or NO2?

I think NO2, because one of its oxygen is missing an electron.
I still think something is wrong with the N in the first formula so I'm skipping this one.

Lactic acid partially dissociates, Ka=1.4x10^-4, to form hydronium ions and conjugate base. Determine kb for this base.

kb=10^-14/ (1.4x10^-4)= 7.1x10^-11
Is that how I am supposed to do this?
Yes, the procedure is correct although I didn't check the math. Kb = Kw/Ka.

Answer 2

I read Bob Pursley's answers to your later post of this same question. For number 1, his answer is better than mine because the problem just says solution and we don't know the pH of the solution. My answer is correct because I put enough disclaimers on it (such as neutral solution) etc but the problem clearly states solution and not neutral solution.

Answer 3

how many grams are produced from 1.5L of 6M HCl