The lowest temperature at which an oil gives sufficient vapours to form an explosive mixture with air is known as -
(A) Flash Point
(B) Smoke Point
(C) Explosive Point
(D) Acidic Flux
Answer: (A) Flash Point
Explanation: The flashpoint of a liquid is the lowest temperature at which the liquid gives off enough vapour to be ignited (start burning at the surface of the liquid. Sometimes more than one flashpoint is reported for a chemical.
More Question
Question: Which of the following metals in pure form has the highest melting point?
(A) Tungsten
(B) Copper
(C) Platinum
(D) Gold
Question: All the mixtures containing a solid and a liquid can be separated by -
I. Centrifugation
II. Evaporation
III. Crystallisation
IV. Chromatography
Correct code is -
(A) Only I
(B) Only II and III
(C) I, II, III and IV
(D) Only III and IV
Question: Which of the following is not a characteristic of a physical change?
(A) It is a temporary change
(B) It is usually an irreversible change
(C) Very little heat (or light) energy is usually absorbed or given out
(D) The mass of a substance does not alter in a physical change
Question: Sound cannot travel through -
(A) Solids
(B) Liquids
(C) Gases
(D) Vaccum
Question: What is the correct ascending order of the following substances in relation to their density (kg/ m(C)?
(A) Aluminium, Iron, Mercury, Gold
(B) Gold, Iron, Aluminium, Mercury
(C) Mercury, Iron, Gold, Aluminium
(D) Iron, Gold, Mercury, Aluminium
Question: Which of the following metals exists in the liquid state?
(A) Sodium
(B) Mercury
(C) Silver
(D) Chromium
Question: Which of the following metals is not strong?
(A) Sodium
(B) Gold
(C) Silver
(D) Iron
Question: The device used for producing electric current is called -
(A) Generator
(B) Galvanometer
(C) Ammeter
(D) Motor
Question: Sun derives its energy from -
(A) The fusion of hydrogen nuclei into helium nuclei
(B) The fusion of helium nuclei into hydrogen nuclei
(C) The fission of hydrogen nuclei
(D) The fission of helium nuclei
