Advertisements
Advertisements
प्रश्न
Dilute NaOH can be tested with
(a) red litmus paper
(b) blue litmus paper
(c) lime water
(d) Na2CO3
Advertisements
उत्तर
(a) red litmus paper
Sodium hydroxide when dissolved in water undergoes the following
reaction:
NaOH(s) + aqs → Na+(aq) + OH−(aq)
The dissociated OH− ions turn moist red litmus paper blue.
APPEARS IN
संबंधित प्रश्न
Why should curd and sour substances not be kept in brass and copper vessels?
Dry HCl gas does not change the colour of dry blue litmus paper. Why?
Write a word equation and then a balanced equation for the reaction taking place when:
Dilute hydrochloric acid reacts with magnesium ribbon.
Complete and balance the following chemical equation:
\[\ce{Zn_{(s)} + HCl_{(aq)} ->}\]
Complete and balance the following chemical equation:
\[\ce{Na2CO3_{(s)} + HCl_{(aq)} ->}\]
What happens when an acid reacts with a metal? Give the chemical equation of the reaction involved.
Name the gas evolved when zinc granules are treated/heated with:
Hydrochloric acid solution
What ions are present in the solution of the following substance? (write the symbols only)
Hydrochloric acid
What ions are present in the solution of the following substance? (write the symbols only)
Magnesium hydroxide
Wasp stings can be treated with ______.
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?
Explain the following:
Lead carbonate does not react with dilute HCl.
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.
Write any four physical properties of acids.
A solution of NaCl
(i) will turn red litmus blue
(ii) will turn pH paper green
(iii) will turn blue litmus red
(iv) will not affect litmus
What are strong and weak acids? In the following list of acids, separate strong acids from weak acids.
Hydrochloric acid, citric acid, acetic acid, nitric acid, formic acid, sulphuric acid.
Are all acids corrosive in nature? Name a few acids which are non-corrosive and may be part of our food.
Copper or brass cooking vessels are coated with tin metal. Why?
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:
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?
