Railway Science (Chemistry-Discoveries)

Total Questions: 20

11. Dobereiner made the first observations on ________ as a catalyst. [RRB Group D 15/10/2018 (Afternoon)]

Correct Answer: (d) Pt
Solution:

Catalyst - The substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.

12. Which scientist provided the fundamental theory about the nature of matter ? [RRB Group D 16/10/2018 (Afternoon)]

Correct Answer: (d) John Dalton
Solution:

John Dalton proposed the atomic theory of matter in 1808. According to Dalton’s atomic theory, all matter, whether an element, a compound or a mixture is composed of small particles called atoms. Antoine Lavoisier is known for his law of conservation of mass.

13. The term ‘Mole’ was introduced by _____ around 1896: [RRB Group D 23/10/2018 (Morning)]

Correct Answer: (c) Wilhelm Ostwald
Solution:

‘Mole (mol)’ is the SI unit of amount of substance. One mole (mol) contains exactly 6.022 × 10²³ elementary entities. This number is the fixed numerical value of the Avogadro constant, when expressed in the unit mol⁻¹ and is called the Avogadro number.

14. The nucleus model of the atom was first discovered by: [RRB Group D 23/10/2018 (Evening)]

Correct Answer: (a) Ernest Rutherford
Solution:

Rutherford atomic model : Conclusion - Most of the space is empty. Nucleus - The Center of atom. Positive Charge (Proton) - occupies minimum space. Negative Charge (Electron) - Revolve around the nucleus. Limitation - fails to explain Stability of Atom. Arrangement of electrons was not defined.

15. Who introduced the word 'particle' (mole) in chemistry? [RRB Group D 27/11/2018 (Evening)]

Correct Answer: (c) Wilhelm Ostwald
Solution:

The word “mole” was introduced around 1896 by Wilhelm Ostwald. John Dalton: Introduced the concept of atomic theory. Amido Avogadro: Proposed Avogadro's Law and Avogadro's constant. Lavoisier: Introduced the concept of the Law of Conservation of Mass.

16. Which of the following scientists did not contribute to the creation of the modern periodic table? [RRB Group D 1/12/2018 (Afternoon)]

Correct Answer: (a) Democritus
Solution:

He was a Greek philosopher and discovered the word 'atom’.

17. Who among the following laid the foundation of chemical sciences by establishing two important laws of chemical combination ? [RRB ALP Tier - I (09/08/2018) Afternoon]

Correct Answer: (c) Antoine L. Lavoisier
Solution:

Antoine L. Lavoisier (Father of Modern Chemistry) - He gave Combination laws (Law of conservation of mass). Ernest Rutherford - Discovered alpha and beta rays, and proposed the laws of radioactive decay. The Theory of Democritus states that everything is composed of “atoms”, which are physically, but not geometrically, indivisible. Joseph Louis Proust - Law of Constant Composition.

18. Which of the following scientists had done some calculations for the fifth state of matter ? [RRB ALP Tier - I (14/08/2018) Morning]

Correct Answer: (d) Satyendra Nath Bose
Solution:

Satyendra Nath Bose is associated with research related to the fifth state of matter. Along with Albert Einstein, Satyendranath Bose did calculations for the fifth state of matter and named it “The Bose-Einstein Condensate”.
CV Raman - Raman Effect. Homi Bhabha - Father of Indian Nuclear Program. Vikram Sarabhai - Father of Indian Space Research Organisation (ISRO).

19. Who first discovered that every eighth element has properties similar to that of the first ? [RRB ALP Tier - I (21/08/2018) Evening]

Correct Answer: (d) Newland
Solution:

Newlands Law of Octaves - Every eighth element has similar properties when the elements are arranged in the increasing order of their atomic masses. Classified the known 56 elements into 11 groups based on their similar physical properties.

20. The Brownian Motion was discovered by : [RRB ALP Tier - I (31/08/2018) Afternoon]

Correct Answer: (d) Robert Brown
Solution:

Brownian Motion - The random motion of a particle due to the collisions of gaseous molecules. Examples - The motion of pollen grains on still water, Diffusion of pollutants in the air, Diffusion of calcium through bones, Movement of holes of electrical charge in semiconductors.