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JEE Mains | PYQ

In chromyl chloride test for confirmation of \( \mathrm{Cl^-} \) ion, a yellow solution is obtained. Acidification of the solution and addition of amyl alcohol and \( 10\% \) \( \mathrm{H_2O_2} \) turns organic layer blue indicating formation of chromium pentoxide. The oxidation state of chromium in that is:

On reaction of Lead Sulphide with dilute nitric acid which of the following is not formed?

A transition metal 'M' among Sc, Ti, V, Cr, Mn and Fe has the highest second ionization enthalpy. The spin-only magnetic moment value of \( \mathrm{M^{+}} \) ion is ______ BM (Near integer)
(Given atomic number Sc : \( 21 \), Ti : \( 22 \), V : \( 23 \), Cr : \( 24 \), Mn : \( 25 \), Fe : \( 26 \)))

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

The orange colour of \( \mathrm{K_2Cr_2O_7} \) and purple colour of \( \mathrm{KMnO_4} \) is due to:

Identify correct statements from below:
A. The chromate ion is square planar.
B. Dichromates are generally prepared from chromates.
C. The green manganate ion is diamagnetic.
D. Dark green coloured \( \mathrm{K_2MnO_4} \) disproportionates in a neutral or acidic medium to give permanganate.
E. With increasing oxidation number of transition metal, ionic character of the oxides decreases.
Choose the correct answer from the options given below:

The electronic configuration of Einsteinium is:
(Given atomic number of Einsteinium = \( 99 \))

Diamagnetic Lanthanoid ions are:

Total number of ions from the following with noble gas configuration is __________. \( \mathrm{Sr^{2+}} \, (z = 38), \ \mathrm{Cs^{+}} \, (z = 55), \ \mathrm{La^{2+}} \, (z = 57), \ \mathrm{Pb^{2+}} \, (z = 82), \ \mathrm{Yb^{2+}} \, (z = 70) \) and \( \mathrm{Fe^{2+}} \, (z = 26) \).

Among \( \mathrm{VO_2^+}, \ \mathrm{MnO_4^-} \) and \( \mathrm{Cr_2O_7^{2-}} \), the spin-only magnetic moment value of the species with least oxidizing ability is ______ \( \text{BM} \) (Nearest integer).
(Given atomic member \( \mathrm{V} = 23 \), \( \mathrm{Mn} = 25 \), \( \mathrm{Cr} = 24 \))

Among \( \mathrm{CrO} \), \( \mathrm{Cr_2O_3} \) and \( \mathrm{CrO_3} \), the sum of spin-only magnetic moment values of basic and amphoteric oxides is _______ \( 10^{-2} \) \( \mathrm{BM} \) (nearest integer). {Given atomic number of \( \mathrm{Cr} \) is \( 24 \)}

Number of colourless lanthanoid ions among the following is _______. \( \text{Eu}^{3+}, \text{Lu}^{3+}, \text{Nd}^{3+}, \text{La}^{3+}, \text{Sm}^{3+} \)

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In aqueous solutions \( \mathrm{Cr}^{2+} \) is reducing while \( \mathrm{Mn}^{3+} \) is oxidizing in nature.
Reason (R): Extra stability to half filled electronic configuration is observed than incompletely filled electronic configuration.
In the light of the above statements, choose the most appropriate answer from the options given below:

Match List-I with List-II.

Choose the correct answer from the options given below:

Given are two statements:
Statement (I): Fusion of \( \mathrm{MnO_2} \) with \( \mathrm{KOH} \) and an oxidizing agent gives dark green \( \mathrm{K_2MnO_4} \).
Statement (II): Manganate ion electrolytic oxidation in alkaline medium gives permanganate ion.
In the light of the above statements, choose the correct answer from the options given below;

\( \mathrm{KMnO_4} \) decomposes on heating at \( 513 \, \mathrm{K} \) to form \( \mathrm{O_2} \) along with:

Choose the correct statements from the following.
A \( \mathrm{Mn_2O_7} \) is an oil at room temperature
B \( \mathrm{V_2O_4} \) reacts with acid to give \( \mathrm{VO_2^{2+}} \)
C \( \mathrm{CrO} \) is a basic oxide
D \( \mathrm{V_2O_5} \) does not react with acid
Choose the correct answer from the options given below:

‘A first-row transition metal in its \( +2 \) oxidation state has a spin-only magnetic moment value of \( 3.86 \, \text{BM} \). The atomic number of the metal is:

The transition metal having highest \( 3^{rd} \) ionisation enthalpy is:

The spin-only magnetic moment value of the ion among \( \mathrm{Ti^{2+}} \), \( \mathrm{V^{2+}} \), \( \mathrm{Co^{3+}} \) and \( \mathrm{Cr^{2+}} \), that acts as strong oxidizing agent in aqueous solution is \( \_\_\_\_\_\_\_\_ \) \( \text{BM} \) (Near integer).
(Given atomic number : \( \mathrm{Ti: \, 22} \), \( \mathrm{V: \, 23} \), \( \mathrm{Cr: \, 24} \), \( \mathrm{Co: \, 27} \))

Consider the following reaction \( \mathrm{MnO_2} + \mathrm{KOH} + \mathrm{O_2} \rightarrow A + \mathrm{H_2O} \). Product ‘A’ in neutral or acidic medium disproportionate to give products ‘B’ and ‘C’ along with water. The sum of spin-only magnetic moment values of B and C is ______ \( \text{BM} \). (nearest integer) (Given atomic number of Mn is \( 25 \))

In alkaline medium, \( \mathrm{MnO_4^-} \) oxidises \( \mathrm{I^-} \) to:

Match List I with List II.

Choose the correct answer from the option given below:

The number of element from the following that do not belong to lanthanoids is: Eu, Cm, Er, Tb, Yb and Lu

The fusion of chromite ore with sodium carbonate in the presence of air leads to the formation of products \( A \) and \( B \) along with the evolution of \( \text{CO}_2 \). The sum of spin-only magnetic moment values of \( A \) and \( B \) is ____ B.M. (Nearest integer)
[Given atomic number: \( \text{C}: 6 \), \( \text{Na}: 11 \), \( \text{O}: 8 \), \( \text{Fe}: 26 \), \( \text{Cr}: 24 \)]

The 'spin only' magnetic moment value of \( \mathrm{MO_4^{2-}} \) is ______ \( \mathrm{BM} \).
(Where \( \mathrm{M} \) is a metal having least metallic radii among Sc, Ti, V. Cr. Mn and Zn)
[Given atomic number : Sc \( = 21 \), Ti \( = 22 \), V \( = 23 \), Cr \( = 24 \), Mn \( = 25 \) and Zn \( = 30 \)]

Identify the incorrect pair from the following:

Which of the following acts as a strong reducing agent? (Atomic number: \( \mathrm{Ce} = 58 \), \( \mathrm{Eu} = 63 \), \( \mathrm{Gd} = 64 \), \( \mathrm{Lu} = 71 \))

Identify the correct set of reagents or reaction conditions ‘\( X \)’ and ‘\( Y \)’ in the following set of transformation.

Which of the following compounds show colour due to d-d transition?

The metal that shows highest and maximum number of oxidation state is:

In the reaction of potassium dichromate, potassium chloride and sulfuric acid (conc.), the oxidation state of the chromium in the product is \( (+) \) ________.