Chemistry · Science General

Common Chemical Compounds and Reactions

1,204 Questions

Common chemical compounds and reactions questions test your knowledge of everyday chemicals, their formulas, and their interactions. Topics include properties of acids and bases, hard water chemistry, and compounds like baking soda and plaster of paris. This section is essential for general science preparation.

Acids and basesPlaster of parisHard water chemistryCommon chemical formulasEveryday chemical reactions

Common Chemical Compounds and Reactions Questions

Multiple choice some important compounds of magnesium and calcium the s-block elements chemistry

Sorel cement is the mixture of:

  1. $CaCO _3+H _2O$
  2. $MgCl _2+MgO$
  3. $BaSO _4+CO _2$
  4. $MgO+Na _2HPO _4$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sorel cement is a mixture of magnesium chloride and magnesium oxide.

$5MgO+MgCl _2+13H _2O \rightarrow MgCl _2.5Mg(OH) _2.H _2O$
$3MgO+MgCl _2+11H _2O \rightarrow MgCl _2.3Mg(OH) _2.H _2O$

Multiple choice some important compounds of magnesium and calcium the s-block elements chemistry

During the manufacturing of single superphosphate, excess silicon combines with:

  1. base

  2. acid

  3. water

  4. none
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The reactions occurring  during the production of superphosphate are complex and are usually summarised as follows :

1. $Ca _5(PO _4) _3 F + 5H _2SO _4 \rightarrow 5CaSO _4 + 3H _3PO _4 + HF$
2. $Ca _5(PO _4) _3F + 7H _3 PO _4 + 5H _2O \rightarrow 5Ca(H _2PO _4) _2 H _2O + HF$
These reactions can be combined to give the overall equation :
$2Ca _5(PO _4) _3F + 7H _2SO _4 + 3 H _2O \rightarrow 7CaSO _4 + 3Ca(H _2PO _4) _2 H _2O + 2HF$
There are other reactions occurring at the same time. For example, virtually all the HF reacts with other silica minerals associated with the fluorapatite (silicates, quartz) to form silicon tetrafluoride. These gaseous emissions are recovered as hydroflusilicic acid $(H _2SiF _6)$ in the scrubbing system. Carbonates in the rock also react with sulfuric acid.

Multiple choice some important compounds of magnesium and calcium the s-block elements chemistry

Gypsum is a widely occurring mineral. It is the sulphate of calcium with two molecules of water attached. On heating it loses three-quarters of its water and becomes:

  1. baking soda

  2. plaster of Paris

  3. a pearl

  4. an ultramarine
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
It is prepared by heating Gypsum to a temperature of 373K. When gypsum is heated to a temperature of 373K, it loses three-fourths of its water of crystallization and forms Plaster of Paris.
$\underset{\text{Gypsum}}{CaS{O} _{4}.2{H} _{2}O} \xrightarrow[373 K]{\Delta} \underset{\text{Plaster of Paris}}{CaS{O} _{4}.\cfrac{1}{2}{H} _{2}O} + \cfrac{3}{2}{H} _{2}O$
Multiple choice some important compounds of magnesium and calcium the s-block elements chemistry

Gypsum is added to cement clinker to:

  1. decrease the rate of setting of cement

  2. bind the particles of calcium silicate

  3. increase the tensile strength of the cement

  4. facilitate the formation of colloidal gel
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gypsum plays a very important role in controlling the rate of hardening of the cement. It slows sown the setting of cement so that cement is adequately hardened.

Multiple choice some important compounds of magnesium and calcium the s-block elements chemistry

Calcium sulphate is found in nature in two forms, anhydrous calcium sulphate and hydrated calcium sulphate is heated with coke, sulphur dioxide gas is obtained. When hydrated calcium sulphate is heated at $200^oC$, it forms anhydrous salt.

When calcium sulphate is mixed with conc. $HCl$ and the paste is formed. What colour is obtained when a pinch of this paste is brought near the flame?

  1. golden yellow

  2. brick red

  3. crimson red

  4. apple green
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When calcium sulphate is mixed with conc. HCl the paste is formed. When this paste is brought near the flame, brick red colour is obtained which is the characteristic colour of calcium.


Golden yellow is the characteristic colour of sodium.

Crimnson red is the characteristic colour of strontium.

Apple green is the characteristic colour of barium.

Multiple choice some important compounds of magnesium and calcium the s-block elements chemistry

How can Calcium Suphate be produced from Calcium Fluoride?

  1. ${CaF} _{2}$ ${+}$ ${H} _{2}{SO} _{4}$
  2. ${CaF} _{2}$ ${+}$ ${SO} _{2}$
  3. $CaF _2 + H _2S$

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

Calcium Fluoride is treated with Sulphuric Acid to give Hydrogen Fluoride and a precipitate of Calcium Sulphate. The balanced equation can be written as-
${CaF} _{2}$ ${+}$ ${H} _{2}{SO} _{4}$ ${=}$ ${2HF}$ ${+}$ ${CaSO} _{4}$

Multiple choice some important compounds of magnesium and calcium the s-block elements chemistry

Which of the following statement about magnesium oxide is/are correct?

  1. It is a relatively poor desiccant

  2. The largest consumer of magnesia is refractory industry

  3. It is used for making Portland cement

  4. In medicine, magnesium oxide is used for relief of heartburn and sour stomatch
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation

Magnesium oxide is used in all these applications: it acts as a mild desiccant, is a primary material in the refractory industry, is a component in cement, and is used as an antacid.

Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

Which of the following compounds will not undergo decomposition on passing electricity through aqueous solution?

  1. Sugar

  2. Sodium chloride

  3. Sodium bromide

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

Sodium chloride, sodium bromide, and sodium acetate are all ionic compounds and hence, they dissociate into their respective ions in an aqueous solution. On the contrary, sugar is a covalent compound and hence does not dissociate into ions

Multiple choice chemistry metals chemical properties and uses of metals and non-metals introduction to metals physical properties of non-metals

Which of the following mixtures is used in the preparation of tips of match sticks?

  1. $S +K$
  2. $Sb _2S _3+S$
  3. $K _2Cr _2O _7+S+P$
  4. $P+K$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The heads of safety matches contain antimony trisulfide $Sb _2S _3$, potassium chlorate, sulfur, powdered glass, inert fillers, and animal glue.

Hence option $B$ is correct.

Multiple choice evs food trends types of ecological pyramids the muscular system and digestive system in human beings introduction to human digestive system

Citrate undergoes dehydration to form unstable compound

  1. iso-citrate

  2. succinate

  3. cis-aconitate

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

In step two, an enzyme called aconitase converts citrate into isocitrate. Next, an isocitrate dehydrogenase enzyme oxidizes isocitrate, a six-carbon molecule, to a five-carbon α-ketoglutarate. The carbon that was lost is released as carbon dioxide and one NADH is also formed.

So, the correct option is, 'Isocitrate'.

Multiple choice chemistry chemistry in everyday life metal oxides and non metal oxides reactions of acids and bases properties of acids and bases

The principal products obtained on heating iodine with concentrated caustic soda solution is:

  1. $NaIO\, +\, NaI$
  2. $NaIO\, +\, NaIO _3$
  3. $NaIO _3\, +\, NaI +\ H _2O$
  4. $NaIO _4\, +\, NaI$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

On adding iodine to caustic soda(alkali), hypoiodites are formed and the peculiar smell is of iodoform and pale yellow in color.

$6NaOH + 3I _2 \longrightarrow NaIO _3 +5NaI +3H _2O$

Multiple choice chemistry chemistry in everyday life metal oxides and non metal oxides reactions of acids and bases properties of acids and bases

Oxides that react with acids to form salts are known as :

  1. basic oxides

  2. acidic oxides

  3. amphoteric oxide

  4. none of above
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation
Amphoteric oxides are compounds of oxygen which exhibits both acidic as well as basic characteristics. These oxides when react with acid, undergoes neutralization reaction to form water and salt. This exhibits the basic property of the compounds. Similarly reacts with alkali to form salt and water, exhibiting acidic property. Example: aluminium oxide

Acidic characteristics:
$A{l} _{2}{O} _{3} + 6HCl$ → $2Al^{3+} + 6Cl^{–} + 3{H} _{2}O$

Basic characteristics:
$A{l} _{2}{O} _{3} +2OH^– + 3{H} _{2}O → 2[Al {(OH)} _{4}]^–$