Which one of the following compounds is insoluble in water? a) Na2CO3

b) K2SO4

c) Fe(NO3)3

d) ZnS

ZnS

Explanation: usually salts of alkali metals are well soluble in water.

Also most nitrates are well soluble.

Sulfides of transition metals are generally insoluble in water

answer: e.   sour taste

explanation: acids are those substances which dissociates in water to give ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. acids are sour in taste. example: hcl

bases are those substances which dissociates in water to give ions or accepts ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. bases are bitter in taste. bases are slippery in nature.