D & f- BLOCK ELEMENTS practice · Mixed difficulty

Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following are the characteristic properties of interstitial compounds?

I. They have high melting points in comparison to pure metals.

II. They are very hard.

III. They retain metallic conductivity.

IV. They are chemically very reactive.

Choose the correct option.

The composition of duralumin is :

A compound of iron exists as a dimer in vapour state. It is hygroscopic in nature and dissolves in water
giving brown acidic solution. The compound is :

Most common oxidation states of Ce (cerium) are

A metal which is ‘not’ affected by conc. ${\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4},\mathrm{\;HN}{\mathrm{O}_3}$ or alkalies forms a compound $X$. This compound $X$ can be used to give a complex which finds its application for toning in photography. The metal is:

The element californium belongs to the family of:

Molten Ag absorbs about ……… times of ${\mathrm{O}_2}$:

The magnetic moment in Bohr's magneton (BM) of $\left[{Fe}({CN})_6\right]^{4-}$ and $\left[{PtCl}_4\right]^{2-}$ respectively are

Which is used as substitute for platinum in jewellery?

Which of the following statements is correct?

The catalytic activity of transition metals and their compounds is ascribed mainly to:

Which of the following is amphoteric?

Assertion: ${C}-{O}$ bond in metal carbonyls is long.

Reason: There is delocalisation of electrons from filled $d$ orbitals into the empty orbitals on the $CO$ ligands.

The product(s) obtained when $\mathrm{KMnO}_4$ and $\mathrm{HCl}$ react together to form $\mathrm{H}_2 \mathrm{O}$ and $\mathrm{Cl}_2$ along with:

Zinc reacts with conc. ${\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4}$ to produce:

Lanthanoids and actinoids resembles in:

The substance that sublimes on heating is:

Two of the constituents of German silver are

Fool’s gold is

Powdered silver ore is treated with NaCN solution and air is bubbled through the mixture to give:

Bronze is a mixture of

Assertion : Actinoids can posses $+4$ O.S. more easily then lanthanoid.

Reason: 4f, 5d, 6s have almost same energy levels.

Choose the example of paramagnetic substance.

Effective magnetic moment of $\mathrm{S}{\mathrm{c}^{3 + }}$ ion is

$\mathrm{A}$ and $\mathrm{B}$ formed in the following reactions are:

$\begin{aligned} & \mathrm{CrO}_2 \mathrm{Cl}_2+4 \mathrm{NaOH} \rightarrow \mathrm{A}+2 \mathrm{NaCl}+2 \mathrm{H}_2 \mathrm{O} \\ & \mathrm{A}+2 \mathrm{HCl}+2 \mathrm{H}_2 \mathrm{O}_2 \rightarrow \mathrm{B}+3 \mathrm{H}_2 \mathrm{O} \end{aligned}$

An aqueous solution of $\mathrm{CuS}{\mathrm{O}_4}$ and $\mathrm{N}{\mathrm{H}_4}\mathrm{OH}$ gives a deep blue complex of:

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element which shows highest magnetic moment.

Assertion: Europium (II) is more stable than cerium (II).

Reason: Cerium salts are used as catalyst in petroleum cracking.

The electronic configuration of $\mathrm{Cu}(\mathrm{II})$ is $3 d^9$, whereas that of $\mathrm{Cu}(\mathrm{I})$ is $3 d^{10}$. Which of the following is correct?

The transition element having least enthalpy of atomisation is