Advertisements
Advertisements
प्रश्न
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
Advertisements
उत्तर
To prevent rusting, a layer of zinc metal is applied on iron sheets.
Reason:
Zinc is a non-corrosive metal. Therefore, layer of zinc prevents rusting.
APPEARS IN
संबंधित प्रश्न
The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder, it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change − A), then it burns (Change − B). The following statements pertain to these changes. Choose the correct one.
Complete and balance the following chemical equations
Na + H2 O →
Define precipitation reaction.
FILL IN THE BLANK
Negatively charged ions are called ..........
Explain the term reactant and product giving examples.
When hydrogen burns in oxygen, water is formed; when electricity is passed through water, hydrogen and oxygen are given out. Name the type of chemical change involved in the two cases.
What do you understand by precipitation reaction? Explain with examples.
What do you observe? When
Barium chloride is added to sodium sulphate solution
Name: A brown gas
Give a chemical test to distinguish between the following gases.
SO2 and Cl2
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.
| Heat on ammonium dichromate | Name of neutral gas evolved |
State the following reaction represent oxidation or reduction.
\[\ce{Ag->Ag+}\]
State whether the following reaction is oxidation or reduction.
\[\ce{Na->Na+}\]
Give a balanced equation for a reaction involving the evolution of gas on the addition of dilute acid to sodium sulphite.
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.
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
Classify the following as physical or chemical properties
Most metal oxides form alkalis on interacting with water.
Magnesium + oxygen → magnesium oxide.
2Mg + O2 → 2Mg O
Is the conversion of milk into ice cream a chemical change?
