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प्रश्न
Name the gases which Turn moist red litmus blue.
उत्तर
NH3
APPEARS IN
संबंधित प्रश्न
What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Compounds, which in their molten state allow an electric current to pass through them are called
- electrolytes
- non-electrolytes
- non-conductors
- none of these
MATCH THE COLUMNS
| 1 . `H_2` + `CI_2` `→` 2HCI | a. displacement reaction |
| 2. `2FeCI_3`+ `H_2` `→` `2FeCI_2` +2HCI` | b. addition of an electronegative redical |
| 3. Fe + `CuSO_4` `→``FeSO_4` +Cu` | c. removal of an electronegative redical |
| 4. `2H_2O` +`4NO_2`+`O_2` `→` `4HNO_3` | d.reduction by adding hydrogen |
| 5. 3Fe +`3CI_2` `→` `2FeCI_3` | e.electrolysis of water |
| 6. `FeCI_3`+ 3NaOH `→``Fe(OH)_3``↓`+NaCI | F.double decomposition,precipitation reaction |
| 7.`2H_2O` `→` `2H_2``↑`+`O_2` | e. combination or synthesis reaction |
What do you observe when :
an iron nail is kept in tap water for few days
Balance the following equation :
Fe + H2O → Fe3O4 + H2
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
Rusting of iron is a ______ chemical change.
Explain by writing a word equation.
Respiration is a chemical change.
Give an example of the following chemical changes.
A reaction where colour change is noticed.
What do you observe when H2S is passed through a lead nitrate solution.
Write your observation and a balanced equation in the case of the following substances being heated.
Copper carbonate.
Give examples of exothermic reactions i.e. heat evolved in each of the following:
(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.
Select the correct answer for the following options:
The gas which reacts with oxygen to give a neutral liquid.
Explain the term chemical reaction with special reference to reactants and products.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
Arrange the following statements in correct sequence:
- One side is water-loving and other water-hating molecules.
- When you agitate the cloth, the dirt is surrounded by many molecules and taken away from the cloth.
- The dirt surrounded by the detergent molecules floats in the water making it dirty.
- Finally, the cloth is clean.
- The detergent molecules have two sides.
- Water hating goes and joins with dirt and oil in the cloth while the water-loving joins with the water molecules.
Classify the following processes into physical or chemical changes:
(i) Beating of aluminium metal to make aluminium foil.
(ii) Digestion of food.
(iii) Cutting of a log of wood into pieces.
(iv) Burning of crackers.
Iron and rust are the same substances.
How would you show that the settling of curd is a chemical change?
______ is the chemical name of slaked lime.
