Railway Science (Chemistry-Common Name)

Total Questions: 34

31. The chemical formula of C₁₂H₂₂O₁₁ is: [RRB Group D 4/12/2018 (Evening)]

Correct Answer: (c) lactose
Solution:

It is more commonly known as milk sugar since this disaccharide is found in milk. It is composed of β-D-galactose and β-D-glucose. Fructose (molecular formula: C₆H₁₂O₆), Glucose (molecular formula: C₆H₁₂O₆). Galactose (molecular formula: C₆H₁₂O₆).

32. Solid carbon dioxide is known as: [RRB ALP Tier - I (14/08/2018) Afternoon]

Correct Answer: (a) dry ice
Solution:

Dry ice is the solid form of carbon dioxide (CO₂). It does not melt into a liquid when heated. Instead, it changes directly into a gas (a process known as sublimation). Carbon dioxide (CO₂) is colorless and odorless.

33. What is the molecular formula of Calcium Phosphate ? [RRB ALP Tier - I (30/08/2018) Evening]

Correct Answer: (c) Ca₃(PO₄)₂
Solution:

Calcium phosphate (Tricalcium Phosphate) can be described as a calcium salt of phosphoric acid. Calcium phosphate is prepared by the reaction of phosphoric acid with calcium hydroxide.
The chemical reaction equation for the same is- 3Ca(OH)₂ + 2H₃PO₄ ⟶ Ca₃(PO₄)₂ + 6H₂O. Calcium phosphate is insoluble in ethanol, and acetic acid but soluble in dilute nitric acid and hydrochloric acid. It slightly dissolves in water.

34. Which of the following statements is/are true or false ? [RRB ALP Tier - I ( 31/08/2018 (Evening)]

A) Natrium is the Latin name of Sodium
B) Argentum is the Latin name of Silver

Correct Answer: (b) Both statements A and B are true
Solution:

Element (Symbol) - Copper (Cu), Potassium (K), Gold (Au), Lead (Pb), Iron (Fe), Tin (Sn), Gold (Au), Mercury (Hg). Sodium (Na): Discovered - Humphry Davy, Atomic Number (11), Atomic Weight (amu, g/mol) 22.98977. Silver (Ag): Atomic number (47), atomic weight (107.868).