Test Index

CBSE Class 10 Science 2020 Outside Delhi Set 1

© examsnet.com
Question : 16 of 30
Marks: +1, -0
Complete and balance the following chemical equations :
(i) NaOH(aq)+Zn\mathrm{NaOH}(\mathrm{aq}) + \mathrm{Zn} (s) →\rightarrow
(ii) CaCO3\mathrm{CaCO}_3 (s) +H2O(l)+CO2+ \mathrm{H}_2\mathrm{O}(\mathrm{l}) + \mathrm{CO}_2 (g) →\rightarrow
(iii) HCl(aq)+H2O(l)→\mathrm{HCl}(\mathrm{aq}) + \mathrm{H}_2\mathrm{O}(\mathrm{l}) \rightarrow
OR
During electrolysis of brine, a gas ' GG ' is liberated at anode. When this gas ' GG ' is passed through slaked lime, a compound ' CC ' is formed, which is used for disinfecting drinking water.
(i) Write formula of ' GG ' and ' CC '.
(ii) State the chemical equation involved.
(iii) What is common name of compound ' CC '?
Give its chemical name.
Solution:  
(i) 2NaOH+Zn→t∘CNa2ZnO2+H22 \mathrm{NaOH} + \mathrm{Zn} \xrightarrow{t^{\circ}\mathrm{C}} \mathrm{Na}_2\mathrm{ZnO}_2 + \mathrm{H}_2
(ii) Calcium carbonate will react with water that is saturated with carbon dioxide to form the soluble calcium bicarbonate.
CaCO3(s)+CO2(g)+H2O(l)→Ca(HCO3)2(aq)\mathrm{CaCO}_3(\mathrm{s}) + \mathrm{CO}_2(\mathrm{g}) + \mathrm{H}_2\mathrm{O}(\mathrm{l}) \rightarrow \mathrm{Ca}(\mathrm{HCO}_3)_2(\mathrm{aq})
(iii) HCl+H2O→H3O++Cl−\mathrm{HCl} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{H}_3\mathrm{O}^+ + \mathrm{Cl}^-
OR
(i) Chlorine gas is given off at the anode. So, GG is Cl2\mathrm{Cl}_2; bleaching powder is produced by the action of chlorine on dry slaked lime [Ca(OH)2][\mathrm{Ca}(\mathrm{OH})_2]. Bleaching powder is represented as CaOCl2\mathrm{CaOCl}_2, so CC is CaOCl2\mathrm{CaOCl}_2.
(ii) Ca(OH)2+Cl2→CaOCl2+H2O\mathrm{Ca}(\mathrm{OH})_2 + \mathrm{Cl}_2 \rightarrow \mathrm{CaOCl}_2 + \mathrm{H}_2\mathrm{O}
(iii) Compound CC is bleaching powder, its chemical name is calcium hypochlorite.
© examsnet.com
Go to Question:
Prev Question
Next Question