Chemistry

Chemical Compounds and Reactions

329 Questions

Chemical compounds and reactions involve understanding the properties, colors, and formation of various chemical substances. Questions focus on identifying precipitates, observing color changes during reactions, and naming common compounds. This topic is a fundamental part of the chemistry syllabus for competitive exams.

identifying precipitateschemical reaction colorscompound namingcolloidal particle propertiesacid base reactions

Chemical Compounds and Reactions Questions

Multiple choice

Which of the following statements is/are incorrect?

P. CuCl2 is used as a catalyst in the manufacture of ammonia by Haber process. Q. CuCl exhibits blue colour in aqueous solution.
R. Fractional crystallisation of metals to get maximum pure form is known as zone refining.

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because iron (Fe) is used as a catalyst in the manufacture of ammonia by Haber process, while CuCl2 is used as a catalyst in Deacon process for the preparation of Cl2 from HCl. CuCl in aqueous solution form Cu+ ions, which possess no colour due to the presence of completely filled d orbitals.

Multiple choice

Which of the following statements is correct?

  1. SO2 acts as temporary bleaching agent, while Cl2 acts as permanent bleaching agent.

  2. SO2 acts as permanent bleaching agent, while Cl2 acts as temporary bleaching agent.

  3. Both SO2 and Cl2 act as temporary bleaching agents.

  4. Both SO2 and Cl2 act as permanent bleaching agents.

  5. SO2 can be used as bleaching agent, while Cl2 cannot be used.<!--?xml:namespace prefix = o /--><o:p></o:p><o:p></o:p>
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

SO2 bleaches due to reduction which is temporary bleach and can be converted to its original by atmospheric oxygen, whereas Cl2 bleaches due to oxidation which is permanent bleach.

Multiple choice

Which of the following statements is incorrect?

  1. PdCl2 is used in Wacker process for the preparation of ethanal.

  2. MnO is used in dry battery cells.

  3. Tungsten is used in incandescent lamps.

  4. KMnO4 is used as a bleaching agent for textile fibres.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Manganese dioxide (MnO2) is used in dry battery cells.

Multiple choice

The elements whose oxides can turn litmus solution blue are

  1. carbon and sulphur

  2. sodium and carbon

  3. potassium and magnesium

  4. magnesium and sulphur
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Oxides of potassium and magnesium turn litmus solution blue because potassium and magnesium are metals. Metals form basic oxides which turn litmus solution blue.

Multiple choice

Which among the following transition metal ions are colourless?

  1. Sc3+
  2. Mn2+
    3. Hg2+ 4. Fe3+ 5. Cu+

  1. 1, 2 and 3

  2. 1, 3 and 5

  3. 2, 3 and 4

  4. 2, 4 and 5

  5. 3, 4 and 5
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Transition metal ions exhibit colour due to the presence of unpaired electrons in (n−1) d-orbitals which undergo d-d transition. The metal ions not having unpaired electrons (n−1)d0 or having completely filled d orbital (n−1)d10 do not absorb radiations in visible region, since d-d transitions are not possible. Hence, they are colourless ions. Sc3+ (3d0), Cu+ (3d10), and Hg2+ (5d10): All are colourless