Can someone explain Q4, 22 of w08 paper, thanks
For Q4, recall that IONIC COMPOUNDS are SOLUBLE in water while COVALENT COMPOUNDS are NOT.
In the first method, X, i.e the ionic salt, will dissolve in the water, as is soluble, leaving Y behind.
Y, as a solid residue, may be obtained via filtering, where X is in solution.
In method 2, Usually both DO NOT dissolve in ethanol.
So only method one is workable, thus the answer is B.
In Q22,
experiment 1 is a simple test for the presence of ammonium ion. recall that sodium hydroxide is added to an ammonium containing compound. Alkaline ammonia gas will produce on heating, turning the red paper blue, and the other blue will remain blue.
In experiment 2, a soluble salt CANNOT react with an acid, so no reaction, thus no change in colour of litmus paper.
Thus ans is D.