Advertisements
Advertisements
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.
Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.
उत्तर १
The formation of lactic acid is what turns the milk into curd; therefore, it will result in the pH changing below 6.
उत्तर २
The pH of milk is 6. As it changes to curd, the pH will reduce because curd is acidic in nature. The acids present in it decrease the pH.
APPEARS IN
संबंधित प्रश्न
Do basic solutions also have H+ (aq) ions? If yes, then why are these basic?
Five solutions, A, B, C, D and E, when tested with universal indicator, showed pH as 4, 1, 11, 7 and 9, respectively. Which solution is
- neutral?
- strongly alkaline?
- strongly acidic?
- weakly acidic?
- weakly alkaline?
Arrange the pH in increasing order of hydrogen-ion concentration.
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.
What colour do the following indicators turn when added to a base or alkali (such as sodium hydroxide)?
litmus
Fill in the blank in the following sentences:
Acids have a ..........................taste and they turn..........................litmus to..........................
Fill in the blank in the following sentences:
Those substances whose smell (or odour) changes in acidic or basic solution are called .......................... indicators.
Fill in the following blank with suitable words:
Neutral substances have a pH of ................
What is a universal indicator? For what purpose is it used?
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.
Someone put some universal indicator paper onto wet soap. The pH is 8. What does this tell you about the soap?
A solution turns phenolphthalein indicator pink. The most likely pH of this solution will be:
(a) 6
(b) 4
(c) 9
(d) 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?
The salt whose aqueous solution will turn blue litmus to red is:
(a) ammonium sulphate
(b) sodium acetate
(c) sodium chloride
(d) potassium carbonate
Hibiscus flower is an example for natural indicator.
Turmeric and litmus are _________ acid-base indicators.
Neutral substances do not bring about any change in colour of indicators.
Take a small beetroot vegetable and cut it into pieces. Boil them in hot water and filter the extract. Take two test tubes. Take sodium hydroxide solution in one test tube and vinegar or lemon juice in another test tube. Add beetroot extract slowly. Observe the colour change. What do you infer?
A milkman adds a very small amount of baking soda to fresh milk. Why does this milk take a long time to set as curd?
