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प्रश्न
When phenolphthalein is added to NaOH, the colour of the solution will become _________.
- colourless
- red
- pink
- yellow
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उत्तर
pink
When phenolphthalein is added to NaOH, the colour of the solution will become pink
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संबंधित प्रश्न
Dilute NaOH can be tested with
(a) red litmus paper
(b) blue litmus paper
(c) lime water
(d) Na2CO3
What do we observe on pouring acetic acid on red and blue litmus papers?
(A) Red litmus remains red and blue litmus turns red.
(B) Red litmus turns blue and blue litmus remains blue.
(C) Red litmus turns blue and blue litmus turns red.
(D) Red litmus becomes colourless and blue litmus remains blue.
How is the concentration of hydroxide ions (OH−) affected when excess base is dissolved in a solution of sodium hydroxide?
A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains ______.
Write a word equation and then a balanced equation for the reaction taking place when:
Dilute hydrochloric acid reacts with iron filings.
The litmus paper or the litmus solution is obtained from ________ plant
(A) Moss
(B) Lichen
(C) Rose
(D) Hibiscus
Complete and balance the following chemical equation:
\[\ce{Na2CO3_{(s)} + HCl_{(aq)} ->}\]
Which element is common to all acids?
A solution reacts with zinc granules to give a gas which burns with a ‘pop’ sound. The solution contains ______.
Write a balanced chemical equation of the reaction which takes place.
A first-aid manual suggests that vinegar should be used to treat wasp stings and baking soda for bee stings. What does this information tell you about the chemical nature of:
wasp stings?
What would be the colour of litmus in a solution of sodium carbonate?
State one use of bleaching powder (other than bleaching).
Is PbO2 a base or not? Comment.
Which of the following salts does not contain any water of crystallisation?
Common salt besides being used in kitchen can also be used as the raw material for making
- washing soda
- bleaching powder
- baking soda
- slaked lime
Which of the following substance will not give carbon dioxide on treatment with dilute acid?
Take a clean test tube with a holder and pour some dilute hydrochloric acid. Add a few pieces of magnesium ribbon pieces slowly. What do you observe? Now show a burning match stick near the mouth of the test tube. Do you hear any sound? The gas burns with a pop sound. From this, it is observed that hydrogen gas has been formed due to the reaction between acid and metal.
______ & ______ metals do not react with HCl or HNO3.
Two salts 'X' and 'Y' are dissolved in water separately. When phenolphthalein is added to these two solutions, the solution 'X' turns pink and the solution 'Y' does not show any change in colour, therefore 'X' and 'Y' are:
