Explain the "Reduction'' in terms of gain or loss of oxygen with two examples.
Reduction is the loss of oxygen.
For example :
$(i)$ $\mathop {C{O_2}\, + \,{H_2}\, \to \,CO}\limits_{{\text{Removal of oxygen - reduction}}} \, + \,{H_2}O$
$(ii)$ $\mathop {CuO\, + {H_2}\,\xrightarrow{\Delta }\,Cu}\limits_{{\text{Loss of oxgyen - reduction}}} \, + \,{H_2}O$
In equation $(i)$, $CO_2$ is reduced to $CO$ and in equation $(ii)$, $CuO$ is reduced to $Cu$.
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
Write the balanced equation for the following chemical reactions.
$(i)$ Hydrogen $+$ Chlorine $\to $ Hydrogen chloride
$(ii)$ Barium chloride $+$ Aluminium sulphate $\to $ Barium sulphate $+$ Aluminium chloride
$(iii)$ Sodium $+$ Water $\to $ Sodium hydroxide $+$ Hydrogen
Why is the amount of gas collected in one of the test tubes in image double of the amount collected in the other ? Name this gas.
Translate the following statements into chemical equations and then balance them.
$(a)$ Hydrogen gas combines with nitrogen to form ammonia.
$(b)$ Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
$(c)$ Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
$(d)$ Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.