Chemistry — CDS General Knowledge PYQs

Match List-I with List-II and select the answer using the codes given below the Lists :

List-I (Symbol of Element)	List-II (Group of Element)
A. Sm	1. Transition Elements
B. Cs	2. Alkali Metals
C. Os	3. Actinoid Elements
D. Np	4. Lanthanoid Elements

Code :

	A	B	C	D
(a)	4	2	1	3
(b)	4	1	2	3
(c)	3	1	2	4
(d)	3	2	1	4

Consider the following statements regarding matter :

1. Elements cannot be broken down into simpler substances.
2. A compound has variable composition and can be broken down into elements.
3. The solution of sulphur in carbon disulphide is an example of a homogeneous mixture.
   Which of the statements given above is/are not correct ?

Consider the following statements :

1. Concentrated ${\text{H}}_2{\text{SO}}_4$ is used as a dehydrating agent in esterification reaction.
2. The hydrophilic part of soap is oil and it dissolves in water.
3. Nickel is used as a catalyst in converting vegetable oil into fat.
   Which of the statements given above are correct ?

Which one among the following pairs is not correctly matched ?

Consider the following statements :

1. Packaged foods are purged with nitrogen gas in order to prevent their oxidation.
2. Tooth decay starts when pH of the mouth is lower than 5.5.
3. The reactivity of metals decreases in the order : Mg > Fe > Zn.
   Which of the statements given above is/are not correct ?

Which one among the following pairs of compound and chemical formula is not correctly matched ?

Consider the following statements :

1. The temporary hardness in water is due to the presence of bicarbonates of calcium.
2. The permanent hardness in water is due to the presence of soluble chlorides and sulphates of calcium and magnesium.
3. The permanent hardness in water is removed by adding ${\text{Na}}_2{\text{CO}}_3$ to water.
   Which of the statements given above are correct ?

Which one among the following statements regarding micelles is not correct ?

Consider the following statements regarding bases and alkalis :

1. All bases dissolve in water.
2. Bases which are soluble in water are called alkalis.
3. An alkali is soapy to touch, bitter and corrosive.
4. Addition of water to an alkali generates heat.

Which of the statements given above are correct ?

Which of the following statements relating to the Modern Periodic Table is/are correct ?

1. The atomic radius increases on moving from left to right across a period.
2. Germanium, Tellurium, and Copper are transition metals.
3. The two isotopes of Chlorine occupy the same position in the periodic table.
4. The metallic property of Ca, Ba, Be and Sr follows the order : Be < Ca < Sr < Ba.
   Select the answer using the codes given below :