Which of the following oxides is soluble in water

Options

A. `Li_(2)O`
B. `Na_O`
C. `K_(2)O`
D. All of these

Answer

4

Explanation

Generally oxides `(O^(2-))`, hydroxides `(OH^(-))` are insoluble, except `Li_(2)O, LiOH, Na_(2)O, NaOH, K_(2)O, KOH, BaO, Ba(OH)_(2)` which are soluble and `CaO, Ca(OH)_(2), SrO, Sr(OH)_(2)` which are moderately soluble.
Remember these oxides dissolve with evolution of heat and formation of hydroxides.