31 Year NEET Previous Year Questions: The p-Block Elements - 2 - NEET MCQ

Urea (46.6%N). % of N in other compound are : ( NH₄)₂ SO₄ = 21.2%; CaCN₂ = 35.0% and NH₄ NO₃ = 35.0%

The correct answer is option C
Chlorine is more reactive than bromine and it displaces bromine.
If chlorine is added to a solution of potassium bromide, the bromine is replaced by the chlorine forming potassium chloride. Bromine is formed at the same time and can be detected by its colour.
2KBr + Cl₂ ​⟶ 2KCl + Br_2​

KI reacts with CuSO₄ solution to produce cuprous iodide (white precipitate) and I₂ (which gives brown colour) Iodine reacts with hypo (Na₂S₂O₃5H₂O) solution.
Decolourisaiton of solution shows the appearance of white precipitate.

On account of highly stable ns² np⁶ configuration in the valence shell. These elements have no tendency either to lose gain or share electrons with atoms of other elements i.e., their combining capacity or valency is zero. Further all the orbitals in the atoms of these elements are doubly occupied i.e electrons are not available for sharing.

The most abundant rare gas found in the atmosphere is argon and not helium.

HI cannot be prepared by heating iodides with concentrated H₂SO₄ because HI is a strong reducing agent and reduce H₂SO₄ to SO₂ and get themselves oxidised to iodide.

ClO₂ contain s 7 + 12 i.e. 19 electr ons (valence) which is an odd number, i.e. there is (are) free electron(s). Hence it is paramagnetic in nature.

Pure ClO₂ is obtained by passing dry Cl₂ over AgClO₃ at 90°C.

Calcium chlorite is Ca (ClO₂)₂

Due to greater tendency for catenation, sulphur shows property of polyanion formation to a greater extent. For example, in polysulphides such as 

Caro’s acid is H₂SO₅ which contains one S – O – O – H peroxy linkage. It is also known as permonosulphuric acids.

Brown ring test is done for confirmation of

Ozone layer is beneficial to us, because it stops harmful ultraviolet radiations to reach the earth.

Thus in this reaction sulphur (S) is produced.

As th e O.N of the central atom of the compounds increases acidic strength of that compound also increases and on moving from top to bottom in groups acidic strength of oxides also decrease due to decreasing electronegativity in groups.

We know that positive ion is always smaller and negative ion is always larger than the corresponding atom. Therefore the correct order of the size is I^- > I > I⁺

Order of dipole moment decreases as NH₃ > PH₃ > AsH₃ > SbH₃ (Based upon electronegativity)

We know that empirical formula of hypophosphorus acid is H₃PO₂. In this only one ionisable hydrogen atom is present i.e. it is monobasic. Therefore option (1) is correct structural formula of it.

Due to absence of reaction between marble and bromine

Ammonium sulphate is a salt of weak base and strong acid, so it produces acidity. Hence aqueous solution of ammonium sulphate is increases the acidity of soil.

Since ozone can easily lose oxygen atom (nascent oxygen), it acts as a powerful oxidising agent, and hence reacts with hydrogen atoms.

The bond energy of F₂ < Cl₂ due to more repulsion in between non-bonding electrons (2p) of F₂ in comparision to non- bonding pair (3p) repulsion in Cl₂, the bond energy of F₂ < Cl₂.
Bond energy (kJ mol^–1) :

Nitrogen form N₂ (i.e. N ≡ N) but phosphorus form P₄, because in P₂, p_π — p_π bonding is present which is a weaker bonding. 

F is more electronegative than Cl therefore HF bond is stronger than HCl and hence proton is not given off easily and hence HF is a weakest acid.

Thus here oxidation number of Br increases from 0 to +1 and also decreases from 0 to –1.
Thus  it is oxidised as well as  reduced

As oxidation number of central atom in oxyacid increases strength increases.  Hence the correct order of acidic strength is

More the oxidation state of the central atom (metal) more is its acidity. Hence SeO₂ (O. S. of Se = +4) is acidic. Further for a given O.S., the basic character of the oxides increases with the increasing size of the central atom.
Thus Al₂O₃ and Sb₂O₃ are amphoteric and Bi₂O₃ is basic.