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 chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

$S _1$: AgCl with liquid ammonia forms a complex $[Ag(NH _3) _2]^+$.
$S _2$: Ammonium dichromate on heating decomposes to give nitrogen and a green colored compound.
$S _3$: CaNCN on hydrolysis produces a white precipitate and a gas which turns filter paper moistened with copper sulphate solution deep blue.

  1. T T T

  2. T F T

  3. F F T

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

$AgCl+NH _3\rightarrow [Ag(NH _3) _2]^++Cl^-$
$(NH _4)Cr _2O _7\xrightarrow {\Delta}N _2+Cr _2O _3+4H _2O$
$CaNCN+3H _2O\rightarrow \underset {(white\ ppt.)}{CaCO _3}+2NH _3$
So, all the three statements are correct.

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

Which of the following does not react with $AgCl$?

  1. $Na _{2}S _{2}O _{3}$
  2. $NH _{4}OH$
  3. $NaNO _{3}$
  4. $NH _{3}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$AgCl+2NH _{4}OH\rightarrow \left [ Ag(NH _{3}) _{2} \right ]Cl+2H _{2}O$
$AgCl+2Na _{2}S _{2}O _{3}\rightarrow NaCl+Na _{3}\left [ Ag(S _{2}O _{3}) _{2} \right ]$
$AgCl+NH _{3}\rightarrow \left [ Ag(NH _{3}) _{2} \right ]Cl$
So, only $NaNO _{3}$ does not react with AgCl.

Multiple choice chemistry nitrogen and sulfur ammonia-properties and uses ammonia compounds of nitrogen - ammonia

An alkaline earth metal $(M)$ dissolves in liquid ammonia forming a deep blue-black solution. The reaction involved is:

  1. $M + 2NH _{3} \rightarrow M(NH _{2}) _{2} + H _{2}$
  2. $M + xNH _{3} \rightarrow [M(NH _{3}) _{x}]$
  3. $M + 2NH _{4}OH \rightarrow M(OH) _{2} + 2NH _{3}$
  4. $M + (x + 2y) NH _{3}\rightarrow [M(NH _{3}) _{x}]^{2+} + 2[e(NH _{3}) _{y}]^{-}$. (e represents electron)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An alkaline earth metal $(M)$ dissolves in liquid ammonia forming a deep blue-black solution. The reaction involved is $M + (x + 2y) NH _{3}\rightarrow [M(NH _{3}) _{x}]^{2+} + 2[e(NH _{3}) _{y}]^{-}$ (e represents electron).
An alkaline earth metal $(M)$ will lose two electrons to form $M^{2+}$ ions.
$M \rightarrow M^{2+}+2e^-$
Both $M^{2+}$ ions and electrons are solvated (surrounded by ammonia molecules to form $[M(NH _{3}) _{x}]^{2+} + 2[e(NH _{3}) _{y}]^{-}$).

Multiple choice

The law of conservation of matter states that

  1. humans should conserve biodiversity around the world

  2. objects fall toward the earth at the same rate

  3. Matter is never created or destroyed

  4. it is important to conserve all matter
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The law of conservation of matter states that matter cannot be created or destroyed in a chemical reaction, only rearranged.

Multiple choice

Chlorine is a non-metal used in

  1. Bleach

  2. Drinking Water

  3. Swimming Pools

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chlorine is a powerful disinfectant and oxidizing agent used to treat drinking water, maintain swimming pools, and as a component in bleach.

Multiple choice

Furniture stuffing, wood, and foam insulation

  1. chloroform

  2. carbon monoxide

  3. asbestos

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

Formaldehyde is a common indoor air pollutant found in many building materials, including pressed-wood products, furniture stuffing, and foam insulation.