When hydrogen gas is passed over heated copper (II) oxide, copper and steam are formed. Write the balanced chemical equation for this reaction and state

(i) the substance oxidised and

(ii) the substance reduced in the reaction. (2014)

Write the balanced chemical equation for the following reaction and identify the type of reaction and define it.

Iron III oxide reacts with Aluminium and gives molten iron and aluminium oxide. (2012)

Identify the type of reaction from the following equation:

(i) CH₄ + 2O₂ → CO₂ + 2H₂O (ii) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃

(iii) CaO + H₂O→ Ca(OH)₂ (iv) CuSO₄ + Zn → ZnSO₄ + Cu

You might have noted that when copper powder is heated in a china dish, the surface of copper powder becomes coated with a black colour substance.(a) How has this black coloured substance formed?(b) What is that black substance?(c) Write the chemical equation of the reaction that takes place. (CBSE 2011)

Using balanced chemical equation give a difference between displacement and double displacement reaction. (CBSE 2012, 2011)