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प्रश्न
What colours do the following indicators turn when added to an acid (such as hydrochloric acid)?
litmus
उत्तर
Litmus paper: Blue litmus paper turns red to an acid, whereas red litmus paper remains red.
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संबंधित प्रश्न
Fresh milk from cows has a pH of 6. So how does the pH change when this milk is turned to curd? Explain your answer.
Fill in the blank in the following sentences:
Acids have a ..........................taste and they turn..........................litmus to..........................
Why does tooth decay start when the pH of mouth is lower than 5.5?
A beaker of concentrated hydrochloric acid has a pH of 1. What colour will full range universal indicator turn if it is added to this beaker? Is it a strong or a weak acid?
Fill in the following blank with suitable words:
The more alkaline a solution, the............... the pH.
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 |
(a) What would the students have used to measure the pH?
(b) Which solution is the most acidic?
(c) Which solution is the most alkaline?
(d) Which solutions are neutral?
(e) Which solution can be used to treat wasp stings?
(f) Which solutions can be used to treat bee stings?
Which one of the following can be used as an acid- base indicator by a visually impared student?
Neutral substances do not bring about any change in colour of indicators.
Write a note on:
Methyl orange
Take some lemon juice in a tumbler and add baking soda slowly. What do you see? What do you infer from this?
