Why does the colour of copper sulphate solution change when an iron nail is dipped in it ?
When an iron nail is placed in a copper sulphate solution, iron displaces copper from copper sulphate solution forming iron sulphate, which is green in colour.
$\underset{Iron}{\mathop{F{{e}_{(s)}}}}\,+\underset{\begin{smallmatrix}
Copper\text{ }sulphate \\
\left( Blue\text{ }colour \right)~
\end{smallmatrix}}{\mathop{CuS{{O}_{4\left( aq \right)}}}}\,\to \underset{\begin{smallmatrix}
Iron\text{ }sulphate \\
\left( Green\text{ }colour \right)
\end{smallmatrix}}{\mathop{FeS{{O}_{4\left( aq \right)}}}}\,+\underset{Copper}{\mathop{C{{u}_{(s)}}}}\,$
Therefore, the blue colour of copper sulphate solution fades and green colour appears.
Explain the ''Rancidity'' terms with one example.
Which of the statements about the reaction below are incorrect ?
$2 PbO _{( s )}+ C _{( s )} \longrightarrow 2 Pb _{( s )}+ CO _{2( g )}$
$(a)$ Lead is getting reduced.
$(b)$ Carbon dioxide is getting oxidised.
$(c)$ Carbon is getting oxidised.
$(d)$ Lead oxide is getting reduced.
A solution of a substance $‘X’$ is used for whitewashing.
$(i)$ Name the substance $‘X’$ and write its formula.
$(ii)$ Write the reaction of the substance $‘X’$ named in $(i)$ above with water.
Write the balanced chemical equations for the following reactions.
$(a)$ Calcium hydroxide $+$ Carbon dioxide $\rightarrow$ Calcium carbonate $+$ Water
$(b)$ Zinc $+$ Silver nitrate $\rightarrow$ zinc nitrate $+$ Silver
$(c)$ Aluminium $+$ Copper chloride $\rightarrow$ Aluminium chloride $+$ Copper
$(d)$ Barium chloride$+$ Potassium sulphate $\rightarrow$ Barium sulphate $+$ Potassium chloride
What happens when dilute hydrochloric acid is added to iron fillings ? Tick the correct answer.