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प्रश्न
Answer the following question:
What is the universal indicator? Does Mg (OH)2 react with sodium hydroxide? If not, why?
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उत्तर
- Universal indicator is an indicator which is a mixture of several indicators.
- It has a very wide range and can indicate pH value almost from 0 to 14.
- When one or two drops of the universal indicator are added to a solution, it changes its colour. This colour is matched against the colour on a standard colour chart (usually given on its bottle) to find the pH, and the pH value can be read. This indicates the strength of the solution too.
- Universal indicator is available as a solution or in the form of paper strips.
- Mg(OH)2 does not react with sodium hydroxide as both are bases.
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संबंधित प्रश्न
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.
What ions are present in the solution of the following substance? (write the symbols only)
Magnesium hydroxide
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?
- bee stings?
Hydrochloric acid reacts with a metal X to form a gas Y which burns with a ‘pop’ sound. Sodium hydroxide solution also reacts with the same metal X (on heating) to form the same gas Y.
- Name X and Y.
- Write the chemical equation of the reaction of metal X with
- hydrochloric acid, and
- sodium hydroxide solution.
What is the chemical formula of washing soda?
What would be the colour of litmus in a solution of sodium carbonate?
With which substance should chlorine be treated to get bleaching powder?
Explain why, sodium hydrogencarbonate is used as an antacid.
State two uses of the following compound:
Hydrochloric acid
Read the following statements:
I. When a red litmus paper is dipped into reaction mixture of a saponification reaction, it turns blue and the reaction is exothermic.
II. When a blue litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is exothermic.
III. When a red litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.
IV. When a blue litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.
Which of the above statements are correct:
(A) I, and II
(B) II and III
(C) III and IV
(D) I and IV
Phenolphthalein is a synthetic type of indicator.
Answer the following question.
Identify the acid and base which form sodium hydrogen carbonate. Write the chemical equation in support of your answer. State whether this compound is acidic, basic, or neutral. Also, write its pH value.
If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?
Acids present in fruits and vegetables are called ______ acids.
Which acid is present in milk?
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.
Consider the following salt:
NH4X
If in salt NH4X, X is nitrate, then its solution will give what colour with a universal indicator? Why?
The metal that will not produce hydrogen gas when reacted with dilute acids.
Some metals react with acids to produce salt and hydrogen gas. Illustrate it with an example. How will you test the presence of this gas?
