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प्रश्न
Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and the third is a sugar solution. How will you identify them? You have only turmeric indicator.
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उत्तर
Test the liquids one by one by placing a few drops of the three liquids on the turmeric indicator.
- If yellow colour is obtained then the liquid will be hydrochloric acid.
- If red or pink colour is obtained then it will be sodium hydroxide.
- If there is no change then it is a sugar solution.
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संबंधित प्रश्न
Name an indicator which is red in acid solution but turns blue in basic solution.
Why should curd and other sour foodstuffs (like lemon juice, etc.) not be kept in metal containers (such as copper and brass vessels)?
What does the pH of a solution signify?
Name the acids or alkalis used to make car batteries.
The pH of a cold drink is 5. What will be its action on blue and red litmus solutions?
The pH values of three acids A, B and C having equal molar concentrations are 5.0, 2.8 and 3.5 respectively. Arrange these acids in order of the increasing acid strengths.
A sample of rain water turned universal indicator paper yellow. What would you expect its pH to be? Is it a strong or a weak acid?
A group of students measured the pH of some substances they found in their homes. Their results are given in the following table:
| Substance | pH | Substance | pH |
| Apples | 3.0 | Salt | 7.0 |
| Baking soda | 8.5 | Sugar | 7.0 |
| Black coffee | 5.0 | Toothpaste | 9.0 |
| Household ammonia | 12.0 | Vinegar | 3.0 |
| Lemon juice | 2.5 | Washing soda | 11.5 |
| Milk | 6.5 |
- What would the students have used to measure the pH?
- Which solution is the most acidic?
- Which solution is the most alkaline?
- Which solutions are neutral?
- Which solution can be used to treat wasp stings?
- Which solution can be used to treat bee stings?
Neutral substances do not bring about any change in colour of indicators.
Using the knowledge of acids and bases, write a secret message with the help of baking soda and beet root. Explain how it works.
(Hint: Prepare baking soda solution in water. Use this solution to write the message on a sheet of white paper with a cotton bud. Rub a slice of fresh beetroot over the message.)
