What is ammonium hydroxide $(NH_4OH)$?

Give a reason to explain:
$(i)$ Why do aluminium sheets not corrode easily?
$(ii)$ Why is a copper vessel covered with a green coating in the rainy season?

What is the shape of monoclinic sulphur?

Which one of the following properties is not generally exhibited by ionic compounds?

Which metal does not react with cold or hot water,but reacts with steam to produce $H_2$ gas?

What type of compounds are formed when reactive metals like sodium and potassium react with dihydrogen?