classification of elements, chemical bonding, periodicity in properties & physical transformation - Category wise Question and Answer Practice Test with Solutions

Question : 21

An element ‘M’ has an atomic number 9 and its atomic mass 19. The ion of M will be represented by

a) M²⁺

b) M^–

c) M

d) M^2–

Question : 22 [NDA]

In the reaction 4Fe + 3O₂  → 4Fe³⁺ + 6O ²⁻
Which of the following statements is incorrect?

a) Metallic iron acts as a reducing agent

b) $O_2$ acts as an oxidising agent

c) It is a redox reaction

d) Metallic iron is reduced to F$e^{3+}$

Question : 23

Which scientist came up with the concept of a periodic table that included all of the known elements?

a) Dmitri Mendeleev

b) Antoine Lavoisier

c) Joseph Priestly

d) Albert Einstein

Question : 24 [IAS Prelim]

Match List-I (Oxidation number) with List II (The element) and select the correct answer using the codes given below the lists :

a) A-4; B-3; C-1; D-2

b) A-3; B-4; C-2; D-1

c) A-3; B-4; C-1; D-2

d) A-4; B-3; C-2; D-1

Question : 25 [UP (Pre) 1998]

Give a thought to these statements.
Statement (A):
Temperature below 0ºC is achieved by the mixture of salt and ice.
Reason (R):
Salt increases the freezing point of ice.
In the context of above statements which one of the following is correct?

a) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

b) (A) is true, but (R) is false

c) Both (A) and (R) are true and (R) is the correct explanation of (A)

d) (A) is false, but (R) is true