Three liquids are given to you. One is hydrochloric acid; another is sodium hydroxide and third is a sugar solution. How will you identity them? You have only turmeric indicator.
Like the litmus paper, turmeric is also a natural indicator. Turmeric solution turns red, when it comes in contact with bases. It is not affected by acids and neutral substances.
We will put a drop of each of hydrochloric acid; sodium hydroxide and sugar solution on turmeric indicator. The liquid which change the colour of turmeric indicator to red is basic in nature, that is, sodium hydroxide.
Now, we will pour a drop of sodium hydroxide in other two liquids separately. Then, we will put the drops of these liquids on turmeric indicator. The liquid which will not change the colour of turmeric indicator contains hydrochloric acid because sodium hydroxide neutralize the acid and forms a neutral solution. Whereas the liquid which change the colour of turmeric indicator to red is sugar solution. This is because the mixture of base and neutral solution is basic in nature.
Mark “T” if the statement is true and “F” if it is false:
i. Nitric acid turns red litmus blue. (T/F)
ii. Sodium hydroxide turns blue litmus red. (T/F)
iii. Sodium hydroxide and hydrochloric acid neutralize each other and form salt and water. (T/F)
iv. Indicator is a stub stance which shows different colours in acidic and basic solutions. (T/F)
v. Tooth decay is caused by the presence of a base. (T/F)
Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labeled. He has to serve the drinks on the demand of customers. One customer wants acidic drink; another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?
Consider the following statements:
a. Both acids and bases change colour of all indicators.
b. If an indicator gives a colour change with an acid, it does not give a change with a base.
c. If an indicator changes colour with a base, it does not change colour with an acid.
d. Change of colour in an acid and a base depends on the type of the indicator.
Which of these statements are correct?
i. All four ii. a and b
iii. b and c iv. Only d