Chemistry Multiple Choice Questions on “Diazonium Salts Physical Properties”.
1. Aromatic diazonium salts are stable at _____ temperatures.
a) cold
b) room
c) warm
d) high
Answer: a
Clarification: Benzenediazonium salts are stable in cold environment, but readily react with water when the temperature increases even slightly.
2. When a blue litmus paper is dipped in an aqueous solution of benzenediazonium bromide, the litmus paper _____
a) turns red
b) turns orange
c) turns black
d) remains unchanged
Answer: d
Clarification: Benzenediazonium bromide is a salt, made of a positive diazonium group and a negative bromide ion. Thus, it remains neutral to litmus paper.
3. Benzenediazonium chloride is ______ in water.
a) slightly soluble
b) highly soluble
c) insoluble
d) highly insoluble
Answer: b
Clarification: Benzenediazonium chloride is readily soluble in polar solvents like water. However, it is less soluble in solvents like alcohol.
4. Which of the following best describes benzenediazonium chloride?
a) Yellow solid
b) Colourless crystals
c) White powder
d) Oily liquid
Answer: b
Clarification: Benzenediazonium chloride is usually obtained in crystal form. It is unstable and formed for a short period when aniline reacts with nitrous acid. It is a salt with chlorine as the negative group and diazo group as positive.
5. Which of the following diazonium salts is insoluble in water?
a) C6H5N2+Cl–
b) C6H5N2+Br–
c) C6H5N2+HSO4–
d) C6H5N2+BF4–
Answer: d
Clarification: Certain diazonium salts such as fluoroborates are insoluble in water. This makes them stable enough to be dried and stored.
6. Which of the following properties is suitable for all diazonium salts?
a) Water soluble
b) Coloured solids
c) Explosive
d) Unreactive
Answer: c
Clarification: Diazonium salts are unstable and may explode in dry state. Therefore, they are generally used in solution or aqueous state.
7. Benzenediazonium chloride is commercially available in packaged form.
a) True
b) False
Answer: b
Clarification: Because of the highly unstable nature of diazonium salts, they are not commercially available. Instead, they are prepared on demand.
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