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प्रश्न
Circle the odd one out. Give reason for your choice
पर्याय
Growth of a child
Blinking of eye
Rusting
Germination of a seed
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उत्तर
Rusting
Reason: Rusting is undesirable change. Others three are desirable changes.
APPEARS IN
संबंधित प्रश्न
TRUE \ FALSE
The evolution of a gas during a chemical reaction is shown by an arrow pointing downwards. True or false ?
Fill in the blank
A new substance is formed in a _______ change.
Write true or false :
No new substance is formed during a chemical reaction.
A solution of a substance ‘X’ is used for white washing write the reaction of the substance ‘X’ named in (a) above with water.
Match the column in the following table.
| Reactants | Products | Type of chemical reaction |
| BaCl2(aq) + ZnSO4(aq) | H2CO3(aq) | Displacement |
| 2AgCl(s) | FeSO4(aq) + Cu(s) | Combination |
| CuSO4(aq) + Fe(s) | BaSO4↓ + ZnCl2(aq) | Decomposition |
| H2O(l) + CO2(g) | 2Ag(s) + Cl2(g) | Double displacement |
Explain by writing a word equation.
Bubbles are seen on adding lemon juice to baking soda.
Give an example of a reaction where the following are involved
Light
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium dichromate.
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium chloride
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
A coloured substance which leaves a black residue and evolves two gases one of which is acidic and coloured and the other neutral and colourless.
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
______ gas causes tears in our eyes while cutting onions.
The chemical change is ______.
True or False. If false, give the correct answer.
Taking a glass of water and freezing it by placing it in the freezer is a chemical change.
Which of the following is not an “element + element → compound” type reaction?
Silver articles turning black: ______:: Boiling of H2O: physical change ______.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
The chemical name of baking soda is sodium bicarbonate.
Write a note on the following:
Fermentation
______ is the chemical name of limestone.
