Advertisements
Advertisements
प्रश्न
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of dilute acid to an active metal.
Advertisements
उत्तर
Addition of dil. acid to an active metal: Gas is evolved, test tube or flask becomes hot (heat is produced).
APPEARS IN
संबंधित प्रश्न
TRUE \ FALSE
Temperature at which a liquid starts boiling is known as the boiling point of that liquid. True or false ?
True or false
New substances are formed in a chemical change.
A solution of a substance ‘X’ is used for white washing write the reaction of the substance ‘X’ named in (a) above with water.
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
The spoiling of food is a chemical change which is recognized from the generation of certain ______ due to it.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Sodium chloride
Give an example of a reaction where the following are involved
Electricity
Give an example of a reaction where the following are involved
Catalyst
Define a photochemical reaction.
Complete and balance the following reaction:
Pb(NO3)2 + KI →
Give a chemical test to distinguish between the following gases.
SO2 and Cl2
Distinguish by dilute sulphuric acid.
Sodium sulphide and sodium sulphite?
State the following reaction represent oxidation or reduction.
\[\ce{H->H+}\]
Differentiate between the following:
Neutralization reaction and a precipitation reaction.
Higher order Thinking question
A very hot glass on putting in cold water cracks. What does this change indicate?
Can a nickel spatula be used to stir copper sulphate solution? Justify your answer.
Water boiling into water vapour is an example of chemical change.
Iron benches kept in lawns and gardens get____________. It is a _________ change because a new _________ is formed.
______ are substances that speed up the process of a chemical change and it will not undergo any change during the course of the reaction.
Write a note on the following:
Curdling of milk
______ is a chemical substance is used in whitewashing.
