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
Is burning a physical change or a chemical change? Why?
State whether the following is physical or chemical changes.
(energy produced) dissolving sugar in water —
State whether the following is physical or chemical changes.
Slaking of lime —
What will you take into account while identifying the following?
A chemical change in a substance.
Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Natural and man-made change.
Match the examples of changes in List I with the correct.
| List I | List II |
| 1. Expansion of a steel rod on heating | A: Physical change |
| 2. Rotting of eggs | B: Chemical change |
| 3. Milk turning sour | |
| 4. Tarnishing of copper | |
| 5. Separation of naphthalene from a mixture of naphthalene and sodium chloride. |
State which of the following pertain to – chemical changes.
- Substance retains its identity.
- The change is permanent.
- No new substance is formed.
- Is easily reversible.
- Produces one or more new substances by a change in its composition.
- The change is temporary.
- The composition and properties of the original substance are not altered.
Give the reason why the following is considered as chemical changes.
An iron nail kept open in the atmosphere rusts.
Assertion: The explosion of fire cracker is a physical change.
Reason: A physical change is a reversible change.
Cutting a log of wood into pieces is a chemical change.
