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प्रश्न
Water is a neutral substance. What colour will you get when you add a few drops of universal indicator to a test-tube containing water?
उत्तर
A neutral substance has a pH value of 7. When we add a few drops of a universal indicator to a test tube of water (which is a neutral substance), we get a green colour, indicating the neutrality of water.
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संबंधित प्रश्न
What colour will universal indicator show if you add it to the following substances?
(a) potassium hydroxide, pH = 12
(b) soda water, pH = 5
(c) sulphuric acid, pH = 2
Fill in the following blank with suitable words:
Acids have a pH...........than 7.
Explain how pH change in the lake water can endanger the lives of aquatic animals (like fish). What can be done to lessen the danger to the lives of aquatic animals in the lake?
The pH values of six solutions A to F are given below:
A = 0, B = 11, C = 6, D = 3, E = 13, F = 8
Which of the above solutions are (i) acids (ii) alkalis?
(b) Name the acid or alkalis used to make (i) car batteries (ii) explosives (iii) soaps (iv) fertilisers.
Name two common antacids.
Someone put some universal indicator paper onto wet soap. The pH is 8. What does this tell you about the soap?
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?
In basic solution turmeric indicator paper changes from yellow to _______.
Turmeric is used as a _______.
