Advertisements
Advertisements
प्रश्न
Give a reason why – Addition of zinc nitrate to water is a physical change but, the addition of zinc to dilute nitric acid is a chemical change.
Advertisements
उत्तर
Zinc nitrate (soluble in water) dissolves in water and is reversible. No change in composition takes place is a physical change whereas zinc reacts with dil. nitric acid to produce H2 gas which gets oxidized to water by nitric acid (oxidizing agent) and hence is a chemical change.
APPEARS IN
संबंधित प्रश्न
Classify the following as chemical or physical change:
Dissolving common salt in water.
Explain the following giving an example.
Pure substance
State whether the following is physical or chemical changes.
burning of sugar —
Which of the following are chemical changes ?
- decaying of wood
- burning of wood
- sawing of wood
- hammering of nail into wood
State what is meant by the term – interconversion of matter. Is interconversion of matter a physical change or a chemical change.
Photosynthesis is a natural process by which green plants manufacture food in the presence of sunlight.
State the conclusions which can be drawn, to represent photosynthesis as a physical or a chemical change.
Fill in the blank with the appropriate word of the statement given below:
Germination of seeds is considered a __________ change.
Fill in the blanks with the appropriate words of the statement given below:
Heating a piece of iron is considered a __________ change while heating a piece of coal [carbon] is considered a ___________ change.
Give four reasons why the burning of a magnesium ribbon in the air is considered a chemical change.
Match the items of Column I with the items of Column II.
| Column I | Column II | ||
| (a) | Large crystals | (i) | Turns lime water into milky |
| (b) | Depositing a layer of zinc on iron | (ii) | Physical change |
| (c) | Souring of milk | (iii) | Rust |
| (d) | Carbon dioxide | (iv) | Sugar candy (Mishri) |
| (e) | Iron oxide | (v) | Chemical change |
| (f) | Dissolving common salt in water | (vi) | Galvanisation |
