Chemistry - Study Mode

[#471] Colour imparted to the Bunsen flame by strontium salt is
Correct Answer

(D) Crimson red

Explanation

Solution: A flame test is performed by introducing a sample into the blue flame of a bunsen burner and noting any change in the colour of the flame. The tests can be used to detect the presence of some metallic elements in salts. With strontium salt, the colour of Bunsen flame ranges from crimson to red.

[#472] An oxidising agent is a
Correct Answer

(A) An electron acceptor

Explanation

Solution: An oxidising agent is an electron acceptor.

[#473] Silver gets corroded due to ________ in air.
Correct Answer

(B) Hydrogen Sulphide

Explanation

Solution: Silver gets corroded due to presence of Hydrogen sulphide in air.

[#474] Which of the following causes the rusting of iron? a. Oxidation b. Reduction c. Chemical reaction with oxygen d. Chemical reaction with CO 2
Correct Answer

(D) A and C

Explanation

Solution: Oxidation and chemical reaction with oxygen causes rusting of iron.

[#475] Photo-oxidation process is initiated by
Correct Answer

(A) Light

Explanation

Solution: Oxidation is a process in which something (an atom or molecule or substance) loses an electron to something else. Photo-oxidation is therefore the process of oxidation which is caused by shining light on it. Often, light can be used to cause reactions to happen, such as oxidation. The term “photo” comes from “photon” which is light. The effect is facilitated by radiant energy such as UV or artificial light. This process is the most significant factor in weathering of polymers. Photo-oxidation is a chemical change that reduces the polymer’s molecular weight. As a consequence of this change the material becomes more brittle, with a reduction in its tensile, impact and elongation strength. Discolouration and loss of surface smoothness accompany photo-oxidation. High temperature and localized stress concentrations are factors that significantly increase the effect of photo-oxidation.