14 th group elements (p-block) practice · Mixed difficulty

Which statement is false?

Which of the following gives propyne on hydrolysis?

Tin, a silvery white metal exists in:

Carbon suboxide ${\mathrm{C}_3}{\mathrm{O}_2}$ has

Assertion (A): $Ge{F_4}$ and $Si{F_4}$ acts as Lewis bases
Reason (R): $Ge$ and $Si$ have $d -$ orbitals to accept a pair of electrons

${\left[ {S{F_6}} \right]^{2 - }}$ is well known whereas ${\left[ {SiC{l_6}} \right]^{2 - }}$ not. The main reason is/are:
I) Six large chloride ions cannot be accommodated around $S{i^{4 + }}$ due to limitation of its size.
II) Interaction between lone pair of $C{l^ - }$ ion and $S{i^{4 + }}$ ion is not very strong.

The approximate percentage of silica in cement is :

Carbogen is:

Identify the correct statements among the following

(i) standard enthalpies of formation of allotropes of carbon are in the order fullerene > Diamond $>$ graphite
(ii) Boric acid is a monoprotic acid

(iii) Hydrolysed product of $\mathrm{SiCl}_4$ on polymerization produce Silicones

(iv) First ionization enthalpies of $13^{\text {th }}$ group elements follow the order In $< A l \cong G a < T l < B$

Silica dissolves in excess of $HF$ due to formation of:

(A): Zeolites are used as ion exchangers and molecular sieves.

(R): Zeolites consist cavities of different sizes and can trap ${Ca}^{+2}$ ions from hard water and also molecules like ${NH}_3, {CO}_2$

Statement-1: The $C-O$ bond in $CO^{+}$is longer than in $CO$.
Statement-2: In changing from $CO$ to $CO^{+}$, the electron is removed from nonbonding molecular orbital having anti-bonding character.

Sesquioxide of lead is:

In the preparation of amorphous silicon, HF acid is used to remove

What structural characteristics are associated with graphite?

The number of water molecules in gypsum, dead burnt plaster and plaster of Paris, respectively are

Assertion: ${PbI}_4$ is a stable compound.

Reason: Iodide stabilizes higher oxidation state.

${C_{60}}$ an allotrope of carbon contains

Assertion: Surface of diamond is generally impure.

Reason: It has dangling bonds.

Solder is an alloy of :

Minium is:

Assertion: Tin is a highly reactive element, especially at high temperatures.

Reason: The valency of tin is two, which means it can easily form bonds with other elements.

The calorific value of carbon is about &hellip;&hellip;. kcal.

Silicon carbide is used as:

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason
(R).
Assertion (A): Gypsum is used for making fireproof wall boards.
Reason (R): Gypsum is unstable at high temperatures.
In the light of the above statements, choose the correct answer from the options given below

Which form of carbon is used in making boot polish, printing ink, paint and black varnish?

Difference between diamond and graphite is due to:

Which of the following statements are correct

a) Fullerenes have dangling bonds

b) Fullerenes are cage like molecules

c) Graphite is thermodynamically most stable allotrope of carbon

Which of the following oxide is amphoteric?

Buckminster fullerene is