Advertisements
Advertisements
Question
Answer the following question.
Blue litmus solution is added to two test tubes A and B containing dilute HCl and NaOH solution respectively. In which test tube a colour change will be observed? State the colour change and give its reason.
Solution
Test tube A contains dil. HCl and test tube B contains dil. NaOH. On adding blue litmus solution to both the test tubes, the colour of the test tube A will change from blue to red. This is because HCl is acid and acids turn blue litmus to red.
RELATED QUESTIONS
While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Compounds such as alcohols and glucose also contain hydrogen but are not categorized as acids. Describe an activity to prove it.
Why does distilled water not conduct electricity, whereas rain water does?
What colour do the following indicators turn when added to a base or alkali (such as sodium hydroxide)?
(a) methyl orange
What colours do the following indicators turn when added to an acid (such as hydrochloric acid)?
methyl orange
Which gas is liberated when dilute hydrochloric acid reacts with sodium carbonate?
What happens when carbon dioxide gas is passed through lime water for a short time?
Write equations of the reactions involved.
10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be:
(a) 4 mL
(b) 8 mL
(c) 12 mL
(d) 16 mL
In the experimental set-up to show that "the germinating seeds give out carbon dioxide", answer the following questions:
(i) Why do we keep the conical flask airtight?
(ii) Name the substance kept in the small test tube inside the conical flask. Write its role.
(iii) Why does water rise in the delivery tube?
Salt A commonly used in bakery products on heating gets converted into another salt B which itself is used for the removal of hardness of water and a gas C is evolved. The gas C when passed through lime water, turns it milky. Identify A, B and C.
