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प्रश्न
A milkman adds a very small amount of baking soda to fresh milk. Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
उत्तर १
The milkman shifts the pH of the fresh milk from 6 to slightly alkaline because, in an alkaline condition, milk does not set as curd easily.
उत्तर २
Usually, milk is acidic, with a pH of 6. The milkman has added a very small amount of baking soda to the milk to make it alkaline, so that it will not become sour with the formation of lactic acid. The alkaline medium prevents the milk from changing into curd. This is the reason why the milkman has shifted the pH of fresh milk from 6 to slightly alkaline.
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संबंधित प्रश्न
- Both acids and bases change colour of all indicators.
- If an indicator gives a colour change with an acid, it does not give a change with a base.
- If an indicator changes colour with a base, it does not change colour with an acid.
- Change of colour in an acid and a base depends on the type of the indicator.
Which of these statements are correct?
Name an indicator which is red in acid solution but turns blue in basic solution.
Which of the following types of medicine is used for treating indigestion caused by over-eating?
(a) antibiotic
(b) analgesic
(c) antacid
(d) antiseptic
If someone is suffering from the problem of acidity after overeating, which of the following would you suggest as remedy?
Lemon juice, Vinegar, Banking soda solution
Give reason for your choice.
Why does tooth decay start when the pH of mouth is lower than 5.5?
hich is more basic (or more alkaline) : a solution of pH = 8 or a solution of pH = 11?
Fill in the following blank with suitable words:
Neutral substances have a pH of ................
How does a universal indicator work?
What does the pH of a solution signify? Three solution A, B and C have pH values of 6, 4 and 10 respectively. Which of the solutions is highly acidic?
A farmer has found that the pH of soil in his fields is 4.2. Name any two chemical materials which he can mix with the soil to adjust its pH.
A sample of rain water turned universal indicator paper yellow. What would you expect it pH to be? Is it a strong or a weak acid?
Name two common antacids.
When a solution becomes more acidic, does the pH get higher or lower?
The colour of methyl orange indicator in a solution is yellow. The pH of this solution is likely to be:
(a) 7
(b) less than 7
(c) 0
(d) more than 7
Here are some results of solutions tested with universal indicator paper:
| Sulphuric acid | : Red |
| Metal polish | : Dark blue |
| Washing-up liquid | : Yellow |
| Milk of magnesia | : Light blue |
| Oven cleaner | : Purple |
| Car batter acid | : Pink |
Arrange the solutions in order of their increasing pH value (starting with the one with the lowest pH).
What damage could be caused while the pH is low?
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?
Turmeric and litmus are _________ acid-base indicators.
Give names of any two natural indicators.
Few drops of aqueous solution of ammonium chloride are put on a universal indicator paper. The paper turns pink.
Choose the correct option.
