Advertisements
Advertisements
प्रश्न
When an oxide of manganese (A) is fused with KOH in the presence of an oxidising agent and dissolved in water, it gives a dark green solution of compound (B). Compound (B) disproportionates in neutral or acidic solution to give purple compound (C). An alkaline solution of compound (C) oxidises potassium iodide solution to a compound (D) and compound (A) is also formed. Identify compounds A to D and also explain the reactions involved.
Advertisements
उत्तर
The compounds (A), (B), (C) and (D) are given as under:
A = \[\ce{MnO2}\]
B = \[\ce{K2MnO4}\]
C = \[\ce{KMnO4}\]
D = \[\ce{KlO3}\]
The reactions are explained as under:
\[\ce{\underset{(A)}{2MnO2} + 4KOH + O2 -> \underset{(B)}{2K2MnO4} + 2H2O}\]
\[\ce{3MnO^{2-}4 + 4H^+ -> \underset{(C)}{2MnO^{-}4} + MnO2 + 2H2O}\]
\[\ce{2MnO^{-}4 + H2O + Kl -> \underset{(A)}{2MnO2} + 2OH^{-} + \underset{(D)}{KlO3}}\]
APPEARS IN
संबंधित प्रश्न
Calculate magnetic moment of `Fe_((aq))^(2+) ion (Z=26).`
|
`E_((M^(2+)/M)` |
Cr | Mn | Fe | Co | Ni | Cu |
| -0.91 | -1.18 | -0.44 | -0.28 | -0.25 | -0.34 |
From the given data of E0 values, answer the following questions :
(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive
(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements
(3) Which is the stronger reducing agents Cr2+ or Fe2+ ? Give Reason.
Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?
How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
Compare the stability of +2 oxidation state for the elements of the first transition series.
How would you account for the following:
Of the d4 species, Cr2+ is strongly reducing while manganese (III) is strongly oxidising.
NF3 is possible, but NF5 is not. Why?
Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number
Maximum magnetic moment is shown by ____________.
The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.
Which of the following will not act as oxidising agents?
(i) \[\ce{CrO3}\]
(ii) \[\ce{MoO3}\]
(iii) \[\ce{WO3}\]
(iv) \[\ce{CrO^{2-}4}\]
When a brown compound of manganese (A) is treated with \[\ce{HCl}\] it gives a gas (B). The gas taken in excess, reacts with \[\ce{NH3}\] to give an explosive compound (C). Identify compounds A, B and C.
Match the solutions given in Column I and the colours given in Column II.
| Column I (Aqueous solution of salt) |
Column II (Colour) |
| (i) \[\ce{FeSO2.7H2O}\] | (a) Green |
| (ii) \[\ce{NiCl2.4H2O}\] | (b) Light pink |
| (iii) \[\ce{MnCl2.4H2O}\] | (c) Blue |
| (iv) \[\ce{CoC12,6H2O}\] | (d) Pale green |
| (v) \[\ce{Cu2 Cl2}\] | (e) Pink |
| (f) Colourless |
Match the properties given in Column I with the metals given in Column II.
| Column I (Property) | Column II (Metal) | |
| (i) | Element with highest second ionisation enthalpy |
(a) \[\ce{Co}\] |
| (ii) | Element with highest third ionisation enthalpy |
(b) \[\ce{Cr}\] |
| (iii) | \[\ce{M}\] in \[\ce{M(CO)6}\] is | (c) \[\ce{Cu}\] |
| (iv) | Element with highest heat of atomisation |
(d) \[\ce{Zn}\] |
| (e) \[\ce{Ni}\] |
Identify A to E and also explain the reactions involved.
Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.
The element with atomic number 53 belongs to
The element with atomic number 46 belongs to
Which of the following characteristics of transition metals is associated with their catalytic activity?
The given graph shows the trends in melting points of transition metals:
Explain the reason why Cr has the highest melting point and manganese (Mn) has a lower melting point.
