Chemistry

Chemical Compounds and Reactions

505 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 correct?

  1. Lead pencil contains lead sulphide.

  2. Red form of lead oxide is called litharge.

  3. PbO2 is acidic in nature.

  4. All the elements of group 14 form monoxides.

  5. Pb3O4 is called lead sesquioxide.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Red form of lead oxide is called litharge, and the yellow form is massicot.

Multiple choice

Which of the following statements are TRUE?

  1. All halides of alkaline earth metals are ionic in nature.
  2. BeSO4 and MgSO4 are readily soluble in water.
  3. Solvay process can be used for the preparation of potassium carbonate.

  1. Only 1

  2. 1, 2 and 3

  3. Only2

  4. 2 and 3

  5. Only 3
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

BeSO4 and MgSO4 are readily soluble in water. The greater hydration enthalpies of Be2+ and Mg2+ ions overcome the lattice enthalpy factor and therefore their sulphates are soluble in water.

Multiple choice

Chemical formula for bleaching powder is _____.

  1. CaOCl2

  2. CaO2

  3. CaCl2

  4. CaSO4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bleaching powder is chemically known as calcium hypochlorite, with the formula CaOCl2. It is widely used for disinfection and bleaching purposes.

Multiple choice

Which of the following statements is TRUE?

  1. Sol has liquid as dispersed phase and solid as dispersion medium.

  2. For the coagulation of negatively charged arsenious sulfide sol, Al3+ ions are more effective than Ba2+ ions.

  3. Physisorption is independent of the nature of gas.

  4. Emulsions have solid as dispersed phase and liquid as dispersion medium.

  5. Peptisation is the process of converting a colloidal sol into precipitate.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Hardy Schulze law greater is the valency of the coagulating or the flocculating ion, greater is its power to bring about coagulation. Hence, for the coagulation of negatively charged arsenious sulfide sol, trivalent cations (Al3+) are far more effective than divalent (Ba2+) cations.

Multiple choice

Which of the following sets of ions does not give coloured solution?

  1. Cu+, Nb+5 and Cu+2

  2. Ir+4, Mo+4 and Y+3

  3. Ta+5, W+2 and Zn+2

  4. Cr+6, Pt+4 and Re+7

  5. Zr+4, Hf+4 and Os+8
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because the compounds which do not have d-electrons or have filled (n-1)d orbitals (d10) are colourless. Zr+4, Os+8 and Hf+4 have vacant d-orbital (d0), so all are colourless.

Multiple choice

Which one of the following statement is/are true?

P. B3N3H6 is known as inorganic benzene. Q. Boric acid is a dibasic acid. R. Maximum covalence of boron cannot exceed 4. S. BF3 is a Lewis base.

Select the correct answer using codes given below.

  1. P and Q

  2. P and S

  3. Q and R

  4. Q and S

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

Boric acid is a weak monobasic acid. It is not a protonic acid but acts as a Lewis acid by accepting electrons from a hydroxyl ion: B(OH)3 + 2H2O → [B(OH)4]– + H3O+

The number of electrons around the central atom in BF3 is only six. Such electron deficient molecules have tendency to accept a pair of electrons to achieve stable electronic configuration and thus, behave as Lewis acids.

Multiple choice

The chemical composition of hypo used in photography is

  1. silver bromide

  2. sodium thiosulphate

  3. sodium phosphate

  4. silver nitrate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In photography, 'hypo' solution is used as a fixing agent to dissolve unexposed silver halides, and its chemical name is sodium thiosulphate.

Multiple choice

Silver halides are used in photographic plates because they are

  1. oxidised in air

  2. colourless

  3. easily soluble in hypo solution

  4. readily reduced by light
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Silver halides (like silver bromide) are light-sensitive; they decompose into metallic silver when exposed to light, which is the basis of traditional photography.

Multiple choice

Oil forming soap on reacting with NaOH is:

  1. rose oil

  2. paraffin oil

  3. kerosene oil

  4. peanut oil
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Peanut oil is an organic material oil derived from peanuts, noted to have the aroma and taste of its parent legume. Peanut oil is appreciated for its high smoke point relative to many other cooking oils. Its major component fatty acids are oleic acid (56.6%) and linoleic acid (26.7%).[citation needed]. The oil also contains some palmitic acid, arachidic acid, arachidonic acid, behenic acid, lignoceric acid and other fatty acids.It forms soap on reaction with NaOH.