Chemistry
Assertion (A): When a copper coil is dipped in an aqueous solution of silver nitrate, the colour of the solution slowly changes from colourless to blue.
Reason (R): Silver metal is more reactive than copper.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Answer
A is true but R is false.
Explanation — A is true as when copper is placed in silver nitrate solution, solution turns blue due to formation of copper nitrate.
R is false since copper is chemically more reactive than silver, it displaces silver in the aqueous solution of silver nitrate to form copper nitrate.
Cu (s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag (s)
Therefore, A is true but R is false is the correct option.
Related Questions
Assertion (A): A chemical equation must be balanced in order to follow the law of conservation of mass.
Reason (R): A chemical equation called as skeletal equation may not have equal number of atom of each element present in the reactants and products.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): The reaction of an acid with a base to produce salt and water is called a neutralisation reaction.
Reason (R): Neutralisation reaction is a double displacement reaction.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): When energy is absorbed during a chemical reaction, it is said to be an exothermic reaction.
Reason (R): A rise in temperature takes place during an exothermic reaction.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Fill in the blanks:
(a) A reaction in which two or more substances combine to form a single substance is called a …………… reaction.
(b) A …………… is a substance which changes the rate of a chemical reaction without undergoing a chemical change itself.
(c) The formation of gas bubbles in a liquid during a reaction is called …………… .
(d) The reaction between an acid and a base is called …………… .
(e) Soluble bases are called …………… .
(f) The chemical change involving iron and hydrochloric acid illustrates a …………… reaction.
(g) In the type of reaction called …………… two compounds exchange their positive an negative radicals respectively.
(h) A catalyst either …………… or …………… the rate of a chemical change but itself remains …………… at the end of the reaction.
(i) The chemical reaction between hydrogen and chlorine is a …………… reaction.
(j) When a piece of copper is added to silver nitrate solution, it turns …………… in colour.