Chemistry Past Questions And Answers
L . Evaporation. ll. Sublimation. lll. Diffusion. IV. Brownian motion. Which of the above can correctly be listed as evidences for the
- A) I and lll only
- B) ll and lV only
- C) l, ll and lll only
- D) l, ll, lll and lV
An element X, turns a volatile hydride XH3 with a density of 17.2. The relative atomic mass of X is
- A) 34.0
- B) 31.0
- C) 20.0
- D) 14.0
An example of a crystalline substance that does not possess water of crystallization is
- A. potassium trioxonitrate (V)
- B. sodium tetraoxosulphate (VI).
- C. iron (II) tetraoxosulphate (VI)
- D. sodium trioxocarbonate (IV).
An organic compound has an empirical formula CH2O and vapour density of 45. What is the molecular formula? [C = 12, H = 1, O = 16]
- A) C3H7OH
- B) C2H5OH
- C) C3H6O3
- D) C2H4O2
The solvent used for removing grease stain is
- A) turpentine
- B) ammonia solution
- C) ethanol
- D) solution of borax in water
Which of the following methods is commonly used to remove suspended impurities from water?
- A. Fluoridation
- B. Chlorination
- C. Filtration
- D. Distillation
Which of the following properties of elements deceases generally across a period in the Periodic Table?
- A. Electronegativy
- B. Electron affinity
- C. Atomic radluc
- D. lonlzation energy
The following acids are monobasic except
- A. methanoic acid
- B. dioxonitrate lll acid
- C. ethanedioic acid
- D. oxochlorate (l) acid
A pure solid usually melts?
- A. over a wide range of temperature
- B. over a narrow range of temperature
- C. at a lower temperature than the impure one
- D. at the same temperature as the impure one
When starch undergoes complete enzyme-catalyzed hydrolysis, the resulting product is
- A. glucose
- B. maltose
- C. sucrose
- D. fructose