Advertisements
Advertisements
Question
What do you observe when :
an iron nail is kept in tap water for few days
Advertisements
Solution
We observe reddish brown coating on the nail called rust (entirely new substance) is chemical change.
APPEARS IN
RELATED QUESTIONS
What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.
TRUE \ FALSE
Evaporation of water is a physical change. True or false ?
Write true or false :
When potassium iodide solution is added to lead acetate solution a red precipitate is formed.
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.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Hydrogen chloride
Name: Two carbonates do not produce carbon dioxide on heating.
What do you observe when HCI is passed through a silver nitrate solution.
Give a word equation for the following reaction.
A salt which reacts with ammonium hydroxide to give a reddish brown precipitate.
Give reason for the following:
Electrolytic decomposition of water is a reaction involving change of state.
Give a balanced equation for the conversion of an ammonium salt to a basic gas.
Differentiate between the following:
Neutralization reaction and a precipitation reaction.
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.
Burning of paper is a ______ change.
What is the use of indicator?
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.
Iron benches kept in lawns and gardens get____________. It is a _________ change because a new _________ is formed.
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
What changes do you expect?
Write the equation for the process of formation of rust.
Write a note on the catalyst.
