d and f Block Elements · Chemistry · COMEDK

The product and its colour when $\mathrm{MnO}_2$ is fused with KOH in presence of $\mathrm{O}_2$ :

The element with the highest third ionisation enthalpy is:

Which of the following does not correctly represent the order of the property indicated against it?

Pick out the correct option

Assertion(A): Mercury is not considered as a transition element

Reason (R): Mercury is a liquid

Which one of the following species will impart colour to an aqueous solution?

The ion that has a spin only magnetic moment of 5.9 BM is:

The statements given below contains assertion and reason. Choose the correct option

Assertion (A): Cr, Mo and W possess the highest melting point in their respective series of elements.

Reason (R): Cr, Mo and W have stable half-filled electrons in the 'd' shell resulting in strong metallic bonding.

$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ on heating with aqueous NaOH gives $\_\_\_\_$

The basic character of transition metal monoxides follows the order:

Choose the correct metal/ ion from the brackets which -------------------------

A. has chemical reactivity similar to that of the first few members of the Lanthanoids $(\mathrm{Zn}, \mathrm{Ca}, \mathrm{Fe}, \mathrm{Cu})$.

B. has stable $4 \mathrm{f}^7$ electronic configuration, but acts as a strong reducing agent and converts to $\mathrm{M}^{3+}$ state. $\left(\mathrm{Eu}^{2+}, \mathrm{Ce}^{2+}, \mathrm{Pr}^{2+}, \mathrm{Dy}^{2+}\right)$

C. is a colorless ion $\left(\mathrm{Tm}^{3+}, \mathrm{Lu}^{3+}, \mathrm{Gd}^{3+}, \mathrm{Sm}^{3+}\right)$.

D. shows stable +2 oxidation state and is diamagnetic ( $\mathrm{Ce}, \mathrm{Sm}, \mathrm{Ho}, \mathrm{Yb}$ )

Find the correct matches.

Choose the statements which are incorrect in the case of Lanthanoids.

A. $\mathrm{Ce}^{4+}$ is diamagnetic while $\mathrm{Sm}^{3+}$ is paramagnetic.

B. The atomic size of the transition metals having atomic number greater than 71 are very close to that of the elements above them.

C. Lanthanoids react with hot water forming water soluble $\mathrm{Ln}(\mathrm{OH})_3$ with the liberation of $\mathrm{O}_2$.

D. The general electronic configuration of Lanthanoids is $(n-2) \mathrm{f}^{1-14} 5 \mathrm{~d}^0 6 \mathrm{~s}^2$, where $n=6$.

Which is the correct order of increasing number of unpaired electrons in the following ions?

$$\mathrm{A}=\mathrm{Cr}^{2+}(\mathrm{Z}=24) \mathrm{B}=\mathrm{Cu}^{2+}(\mathrm{Z}=29) \quad \mathrm{C}=\mathrm{Ni}^{2+}(\mathrm{Z}=28) \mathrm{D}=\mathrm{Fe}^{3+}(\mathrm{Z}=26)$$

A. $=$ chromate $\mathrm{B}=$ permanganate $\mathrm{C}=$ dichromate

Match the metals in Column II with their characteristic properties given in Column I.

What is the spin only magnetic moment of the metal ion in $\mathbf{P}$ and the oxidation number of Sulphur in the oxidised product Z ?

Identify the correct statement from the following.

An inorganic compound $$\mathrm{W}$$ undergoes the following reactions:

$$ \begin{gathered} W+\frac{\mathrm{Na}_2 \mathrm{CO}_3}{\mathrm{O}_2 / \text { heat }} \rightarrow X+\frac{\mathrm{H}^{+}}{} \rightarrow Y_{(s)} \\ Y(a q)+\mathrm{KCl}(\mathrm{aq}) \rightarrow Z_{(S)} \end{gathered} $$

Z appears in the form of orange crystals and is used as an oxidising agent in acid medium. Identify the compound W.

The Lanthanoid ion which would form coloured compounds is -------------.

Atomic numbers: $$\mathrm{Yb}=70, \quad \mathrm{Lu}=71, \mathrm{Pr}=59, \quad \mathrm{La}=57$$

The metallic ions that have almost same spin only magnetic moment are :

(i) $$\mathrm{Co}^{2+}$$

(ii) $$\mathrm{Mn}^{2+}$$

(iii) $$\mathrm{Cr}^{2+}$$

(iv) $$\mathrm{Cr}^{3+}$$

The correct order of increasing melting point is

Consider the following statements in respect of lanthanides, which of the statements are incorrect?

(i) $$\mathrm{La}(\mathrm{OH})_3$$ is least basic among the hydroxides of lanthanides

(ii) The lanthanide ions $$\mathrm{Yb}^{2+}, \mathrm{Lu}^{3+}$$ and $$\mathrm{Ce}^{4+}$$ are diamagnetic in nature.

(iii) $$\mathrm{Ce}^{4+}$$ can act as an oxidising agent

(iv) $$\operatorname{Ln}$$ (III) compounds are generally colourless

(v) Ionic radii of $$\mathrm{Ce}^{3+}$$ is greater than $$\mathrm{Yb}^{3+}$$

Arrange the following ions in the increasing order of their $$\Delta H_{(\text {hydration})}$$ values.

$$\mathrm{Cr}^{2+}, \mathrm{Co}^{2+}, \mathrm{Mn}^{2+}, \mathrm{Ni}^{2+}$$

The permanganate ion in acid medium acts as an oxidant and gets converted to its lower oxidation state. What would be the spin only magnetic moment of such reduced manganese ion?

Match the compounds given in Column I with their characteristic features listed in Column II

Choose the incorrect statement from the following

$$\mathrm{Ti}^{2+}$$ is purple while $$\mathrm{Ti}^{4+}$$ is colourless because

A volatile compound is formed by carbon monoxide and

Match the following characteristics of transition metals given in Column I with the examples listed in Column II

Find the correct matches of the substances, given in Column I, from their characteristic properties given in Column II.

Identify the incorrect statement.

An aqueous solution of X on addition of hydrogen peroxide in ice cold conditions gives blue colour to the ethereal layer. Then, X can be

In 3d-transmission series, which one has the least melting point?

The electronic configuration of Cr$$^{3+}$$ is

Formation of coloured solution is possible, when metal ion in the compound contains

Which of the following forms a colourless solution in aqueous medium?