Question

Four test-tubes were taken and marked A, B, C and D respectively. 2 mL of solution of \[A{{l}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}\]in water was filled in each of the four test-tubes A, clean iron nail was put in test-tube B, clean copper wire was placed in test-tube D. It was observed that no change occurred in any of the test-tubes.
(A) zinc is more active than aluminium
(B) zinc is more active than copper
(C) copper is more active than aluminium
(D) zinc, iron and copper are less active than aluminium

Answer 1

Hint: To solve this type of question it is very important to remember the reactivity series of elements. The reactivity series is used to provide information about the reactions of metals with water or acids or some displacement reactions.

Complete answer:
Given in the question: Four test-tubes were taken and marked A, B, C and D respectively
2 mL of solution of \[A{{l}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}\] in water was filled in each of the four test-tube
-In test tube B clean iron nail was put
-In test-tube D clean copper wire was placed
Let’s understand what reactivity means, reactivity refers to the chemical reaction of one or more than one substances that interact with each other and form products. The reactivity series is mentioned below-
Potassium – k (most reactive)
Sodium – Na
Calcium - Ca
Magnesium - Mg
Aluminium - Al
Zinc - Zn
Iron - Fe
Tin - Sn
Lead – Pb
Copper – Cu
Silver – Ag
Gold – Au
Platinum – Pt (least reactive)
From the above series we can observe that zinc, iron and copper are less reactive as compared to aluminium. This is the reason why no change occurred in any of the test-tubes.

Hence the correct answer is option (D) i.e. zinc, iron and copper are less active than aluminium

Note: The reactivity series in chemistry in which metals are arranged by their reactivity from highest to lowest is used to provide information about the reactions of metals with water or acids or some displacement reactions. Element in the top of the reactivity series is most reactive and the element at the bottom is least reactive.