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प्रश्न
Circle the odd one out. Give reason for your choice
विकल्प
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
The chemical name of baking soda is ______.
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
What do you observe when iron nail is kept in copper sulphate solution for sometime.
Give reason.
Acidic soil is treated with quick lime.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Miscible liquids having slightly different boiling points can be separated by the
- evaporation
- distillation
- fractional distillation
- sedimentation
FILL IN THE BLANK
In a ............ change, new substances are formed.
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
Explain by writing a word equation.
Bubbles are seen on adding lemon juice to baking soda.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Water
Write the chemical reaction where the following changes are observed.
Gas is evolved
State the original colour of the following substance and colour of residue obtained after heating.
Ammonium dichromate
State the original colour of the following substance and colour of residue obtained after heating.
Lead nitrate
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
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 on strong heating a black residue and evolves two colourless gases one of which is acidic and the other neutral.
Assertion: The formation of iron oxide from iron is a chemical change.
Reason: For the rust to form from iron, it must be exposed to air and water.
Write some materials prepared by chemical changes.
Which of the following are chemical changes?
(i) Decaying of wood
(ii) Burning of wood
(iii) Sawing of wood
(iv) Hammering of a nail into a piece of wood
Write word equations for two chemical reactions with the help of materials given in the box.
| Air, copper sulphate, iron, vinegar, iron oxide, carbon dioxide, iron sulphate, copper, lime water, water |
Which is used as a catalyst during the process of hydrogenation of oils?
When carbon dioxide is passed through lime water ______.
