Free s-Block and p-Block Elements MCQs with Answers

• A. Sb
• B. N
• C. As
• D. P

Explanation: Electronegativity generally increases from left to right across a period and decreases down a group.

• A. Nitrogen
• B. Phosphorus
• C. Carbon
• D. Bismuth

Explanation: Nitrogen exists as N2, a small non-polar molecule with weak London dispersion forces, so it melts at about -210°C, below 0°C.

• A. Ferric hydroxide
• B. Sodium hydroxide
• C. Calcium hydroxide
• D. Aluminium hydroxide

Explanation: Arsenic oxides can be removed by passing the contaminated material through ferric hydroxide, which adsorbs arsenic species strongly on its…

• A. Electronic conviguration of valence shell electrons
• B. Show allotropy
• C. Polymeric
• D. Show same oxidation state

Explanation: Oxygen and sulphur have the same valence-shell pattern, ns2np4, and both show allotropy and catenation or polymeric structures.

• A. ZnS
• B. PbS
• C. HgS
• D. FeS

Explanation: Cinnabar is the red mineral form of mercury(II) sulphide, with the formula HgS.

• A. White
• B. black
• C. red
• D. Violet

Explanation: Black phosphorus is the most stable allotrope at ordinary temperature because its layered structure has the lowest energy among the common…

• A. 1
• B. 3
• C. zero
• D. 2

Explanation: Phosphoric acid is H3PO4 and has three ionisable hydroxyl hydrogens, so one molecule can neutralise three moles of a monobasic base.

• A. 260°C
• B. 360°C
• C. 630°C
• D. 620°C

Explanation: Phosphorus pentoxide, commonly written P2O5 although its molecular formula is P4O10, is highly hygroscopic and sublimes at about 360°C.

• A. Phosphine
• B. Phosphorus
• C. Water
• D. Phosphorus pentoxide

Explanation: On heating, phosphorous acid disproportionates: 4H3PO3 → 3H3PO4 + PH3. Phosphorus is oxidised from +3 to +5 in phosphoric acid, while some…

• A. White
• B. Red
• C. Black
• D. Violet

Explanation: White phosphorus is poisonous because its P4 molecules are highly reactive and can damage tissues; it also ignites readily in air.

• A. Light bearing
• B. Fire
• C. Impure
• D. Tetrahedral

Explanation: The name phosphorus comes from Greek words meaning light-bearer or light-bringer, referring to its faint glow in air.

• A. ionic
• B. covalent
• C. polar
• D. all varieties are possible

Explanation: Nitrogen and phosphorus are non-metals, so they mainly form covalent compounds by sharing electrons.

• A. Arsenic
• B. Phosphorus
• C. Antimony
• D. Bismuth

Explanation: Phosphorus is different because it is a non-metal and commonly appears as a waxy white or red solid.

• A. Beryllium
• B. Carbon
• C. Silicon
• D. Aluminium

Explanation: Aluminium forms the stable tripositive ion Al3+ by losing its three valence electrons and attaining a noble-gas configuration.

• A. As antiseptic in medicine
• B. For washing eyes
• C. In soda bottles
• D. For enamel and glazes

Explanation: Boric acid is used as a mild antiseptic, in some eyewash preparations, and in the manufacture of enamel and ceramic glazes.

• A. Na2B4O7.4H2O
• B. Na2B4O7.5H2O
• C. Na2B4O7.2H2O
• D. Na2B4O7.10H2O

Explanation: Borax normally crystallizes as Na2B4O7.10H2O, but above about 62°C the decahydrate loses water and forms the pentahydrate, Na2B4O7.5H2O.

• A. Hall process
• B. Thermite process
• C. Haber process
• D. Contact process

Explanation: Aluminium is extracted industrially by the Hall-Heroult process, in which purified alumina is electrolysed in molten cryolite.

• A. A1
• B. Si
• C. B
• D. C

Explanation: Tincal is the naturally occurring mineral form of borax, hydrated sodium tetraborate, so it is a mineral of boron.

• A. boron
• B. carbon
• C. silicon
• D. tin

Explanation: The inert pair effect becomes stronger down Group 14 because the ns2 electrons are held more tightly and are less available for bonding.

• A. Cu
• B. Cr
• C. Ni
• D. A1

Explanation: Copper, chromium and nickel form coloured metal metaborates in the oxidising or reducing parts of a borax bead, giving characteristic bead…