What is the difference between displacement and double displacement reactions ? Write equations for these reactions.
In a displacement reaction, a more reactive element replaces a less reactive element from a compound.
$A + BX \longrightarrow AX + B$; where $A$ is more reactive than $B$
In a double displacement reaction, two atoms or a group of atoms switch places to form new compounds.
$AB + CD \longrightarrow AD + CB$
For example :
Displacement reaction :
$CuS{O_{4(aq)}}\, + \,Z{n_{(s)}}\, \to \,ZnS{O_{4(aq)}}\, + \,C{u_{(s)}}\,$
Double displacement reaction :
$N{a_2}S{O_{4(aq)}}\, + \,BaC{l_2}_{(aq)}\, \to \,BaS{O_{4(s)}}\, + \,2NaC{l_{(aq)}}\,$
Write a balanced chemical equation with state symbols for the following reactions.
$(i)$ Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.
$(ii)$ Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.
What do you mean by a precipitation reaction? Explain by giving examples.
What is a balanced chemical equation ? Why should chemical equations be balanced ?
A shiny brown coloured element $‘X’$ on heating in air becomes black in colour. Name the element $‘X’$ and the black coloured compound formed.
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.