Question

Which of the following chemical reactions is excepted to produce a precipitate? A. Ca(OH)2(at) + HCI (aq) B. Ca (OH)2 (at) + Na2SO4 (aq) C. Ca (OH)2 (at) + HNO3 (aq) D. All of the above reactions will produce precipitates

Answer 1

My guess would be `B.`

Explanation:

We should write the stoichiometric equations representing the reactions...

`A. Ca(OH)_2(s) + 2HCl(aq) rarr CaCl_2(aq) + 2H_2O(l)`

`B. Ca(OH)_2(aq) + Na_2SO_4(aq) rarr CaSO_4(s)darr + 2NaOH(aq)`

`C. Ca(OH)_2(s) + 2HNO_3(aq) rarr Ca(NO_3)_2(aq) + 2H_2O(l)`

Calcium sulfate should precipitate when (soluble) sodium sulfate is added to lime water (the which is saturated `Ca(OH)_2(aq)`). Anyway, you will have done the experiment in your course....

And how do you know what calcium salts are insoluble? How else but by experiment, and learning solubilities by rote....