Write balanced chemical equations for the ...

CBSE Class 10 Science Exam 2014 Term 1 Paper

Question : 20 of 36

Marks: +1, -0

Write balanced chemical equations for the following statements :

(i)

\mathrm{NaOH}

solution is heated with zinc granules.

(ii) Excess of carbon dioxide gas is passed through lime water.

(iii) Dilute sulphuric acid reacts with sodium carbonate.

(iv) Egg shells are dropped in hydrochloric acid.

(v) Copper (II) oxide reacts with dilute hydrochloric acid.

Solution:

(i)

\underset{\text{Sodium Hydroxide}}{2\mathrm{NaOH}(\mathrm{aq})} + \underset{\text{Zinc}}{\mathrm{Zn}(\mathrm{s})}

\xrightarrow{\Delta}\underset{\text{Sodium zincate}}{\mathrm{Na}_2\mathrm{ZnO}_2(\mathrm{aq})} + \underset{\text{Hydrogen}}{\mathrm{H}_2(\mathrm{g})}

(ii)

\underset{\text{Lime water}}{\mathrm{Ca}(\mathrm{OH})_2 + }\mathrm{CO}_2 \rightarrow \underset{\text{Calcium carbonate (white ppt.)}}{\mathrm{CaCO}_3(\mathrm{s})} + \mathrm{H}_2\mathrm{O}

\underset{\text{Calcium carbonate}}{\mathrm{CaCO}_3(\mathrm{s})} + \mathrm{CO}_2(\mathrm{g}) + \mathrm{H}_2\mathrm{O}(\mathrm{l}) \rightarrow \underset{\text{Calcium hydrogen carbonate (Soluble in water)}}{\mathrm{Ca}(\mathrm{HCO}_3)(\mathrm{aq})}

(iii)

\mathrm{H}_2\mathrm{SO}_4

(dil.)

+ \underset{\text{Sodium carbonate}}{\mathrm{Na}_2\mathrm{CO}_3(\mathrm{s})} \rightarrow \underset{\text{Sodium sulphate}}{\mathrm{Na}_2\mathrm{SO}_4} + \mathrm{CO}_2 + \mathrm{H}_2\mathrm{O}

(iv)

\underset{\text{Calcium carbonate}}{\mathrm{CaCO}_3(\mathrm{s})} + 2\,\mathrm{HCl}

(v)

\underset{\text{Copper oxide}}{\mathrm{CuO}(\mathrm{s})} + 2\,\mathrm{HCl}(\mathrm{aq}) \rightarrow \underset{\underset{(\text{blue green})}{\text{Copper chloride}}}{\mathrm{CuCl}_2(\mathrm{aq})} + \mathrm{H}_2\mathrm{O}(\mathrm{l})

Go to Question:

Prev Question

Next Question