NCERT Solutions for Chapter: Acids, Bases and Salts, Exercise 1: Exercise

Pema wants to do an activity with hydrochloric acid and lime water (base). Most acids and bases can damage human skin.

Which step must she follow during the activity to ensure safety?

Lime water is a base. Which of the following statements is correct for lime water?

Soha mixed equal amounts of two colourless liquids in a test tube. 
She observed the following: 
• The colour of the liquids did not change. 
• No residue was formed in the test tube. 
• The test tube got hot. 
• No gas bubbles were formed. 
Soha concluded that a chemical change took place in the test tube. Which change confirms her conclusion? 

Anu re-visited a historical monument after 10 years. She noticed that the white monument had turned yellowish. Which event is most likely to have caused the change in colour of the monument?

A base _____.
(i) has a bitter taste
(ii) turns red litmus blue
(iii) turns purple cabbage juice red
(iv) has no effect on turmeric
 

What will happen when purple cabbage solution is added to common salt solution (A) and baking soda solution (B)?

One molecule of ${\mathrm{H}}_3{\mathrm{PO}}_4$ is treated with one molecule of $\mathrm{NaOH}$, two molecules of $\mathrm{NaOH}$ and three molecules of $\mathrm{NaOH}$ separately. Comment on the nature of the products formed and write their names.

A non-metallic element is converted into compound $\mathrm{X}$ after a series of reactions. A little amount of $\mathrm{X}$ turns blue litmus to red. $\mathrm{X}$ on complete reaction with another compound $\mathrm{Y}$ gave the product which did not respond to litmus test. Identify the correct sequence of the reactions.

1. $2{\mathrm{SO}}_2+{\mathrm{O}}_2\to 2{\mathrm{SO}}_3$
2. ${\mathrm{H}}_2{\mathrm{SO}}_4+2\mathrm{KOH}\to {\mathrm{K}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2\mathrm{O}$
3. ${\mathrm{SO}}_3+{\mathrm{H}}_2\mathrm{O}\to {\mathrm{H}}_2{\mathrm{SO}}_4$
4. $\mathrm{S}+{\mathrm{O}}_2\to {\mathrm{SO}}_2$