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 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

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

Which of the following does not react with CuSO4 solution?

  1. Ag

  2. Fe

  3. Mg

  4. Zn

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because these are dependent on the reactivity rules. Hence, more reactive metal displaces the less reactive metal, according to reactivity series silver cannot displace copper therefore it does not react with copper.

Multiple choice

Red lead when heated leaves behind a residue which is reddish brown when hot and yellow when cold. It fuses with glass and also liberates a gas which rekindles a glowing splinter. Which residue is formed?

  1. It is lead mono oxide and acidic in nature.

  2. It is PbO2 and amphoteric in nature.

  3. It is Pb3O4 and amphoteric in nature.

  4. Residue is lead mono oxide and amphoteric in nature
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Correct option. The residue is lead mono oxide and is amphoteric in nature.

Multiple choice

Nessler's reagent gives yellow or brown colour or precipitate when added to solutions containing ammonia or ammonium ions. Among the following which one is mainly used as nessler's reagent ?

  1. Potassium tetrachloroplatinate(II)

  2. Potassium tetraiodomercurate(II)

  3. Potassium peroxochromate

  4. Potassium tetraphenylborate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Potassium tetraiodomercurate(II) is an inorganic compound containing potassium cations and the tetraiodomercurate(II) complex anion. It is mainly used as nessler's reagent, a 0.09 mol/L solution of potassium tetraiodomercurate(II) (K2[HgI4]) in 2.5 mol/L potassium hydroxide, used to detect ammonia.

Multiple choice

Among the following --------------------- is used for frequency doubling diode pumped solid-state lasers.

  1. potassium titanyl phosphate

  2. potassium thiocyanate

  3. potassium hydrogenacetylenedicarboxylate

  4. deuterated potassium dihydrogen phosphate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Potassium titanyl phosphate (KTiOPO4) or KTP is a non-linear optical material which is commonly used for frequency doubling diode pumped solid-state lasers such as Nd:YAG and other neodymium-doped lasers. The material has a relatively high optical damage threshold (~15 J/cm²), a great optical non linearity and excellent thermal stability in theory.

Multiple choice

White phosphorus is formed by the combination of

  1. CaO + P2O5

  2. PBr3 + Hg

  3. P4 + Na

  4. Ca3(PO4)2 + SiO2 + C

  5. (1) and (2) are both correct.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because the white phosphorus is manufactured from the calcium phosphate by modern electrothermic process. A mixture of phosphorite or bone ash, silica and coke in electric furnace, at about 15000C, the vapour of phosphorus are taken for cold water condensation as a form of white phosphorus.