Give a reason for each of the following:
(i)[1.0]
$\text{Cu}^{2+}$ salts are paramagnetic, while $\text{Cu}^+$ salts are diamagnetic.
(ii)[1.0]
$\text{Mn}^{2+}$ compounds are more stable than $\text{Fe}^{2+}$ compounds.
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d-and f-Block Elements - ISC Class 12 Chemistry Questions with Answers, Page 3
50 past-paper questions on d-and f-Block Elements from ISC Class 12 Chemistry papers (2027-2018), newest first, in full. Questions 41-50 are on this page, 20 to a page. Tap "Show answer" under a question to see its answer.
Nothing matches. Try fewer letters.
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:
(two, four, $\text{sec}^{-1}$, diamagnetic, acetaldehyde, $\text{mol}^{-1}\text{L }\text{sec}^{-1}$, paramagnetic, formaldehyde, acetone, ethanol)
(i)[1.0]
When the concentration of a reactant of first order reaction is doubled, the rate of reaction becomes ___________ times. The unit of rate constant ($k$) for the first order reaction is ___________.
(ii)[1.0]
The transition metals show ___________ character because of the presence of unpaired electrons while $\text{Cu}^+$ is ___________ because its electronic configuration is $[\text{Ar}]3d^{10}$.
(iii)[1.0]
Calcium formate on distillation gives ___________ but the distillation of calcium formate and calcium acetate gives ___________.
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(i)
What is the basic difference between the electronic configuration of transition and inner transition elements?
(ii)
Why are $\text{Zn}^{2+}$ ions colourless while $\text{Ni}^{2+}$ ions are green in colour?
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Explain the following:
(i)
Transition metals and their compounds generally exhibit a paramagnetic behaviour.
(ii)
There is an increase in density of elements from titanium ($Z = 22$) to copper ($Z = 29$) in the 3d series of transition elements.
(iii)
$\text{K}_2\text{Cr}_2\text{O}_7$ acts as a powerful oxidising agent in acidic medium.
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Complete and balance the following chemical equations.
(i)
$\text{KMnO}_4 + \text{H}_2\text{SO}_4 + \text{H}_2\text{C}_2\text{O}_4 \rightarrow$ ______ + ______ + ______ + ______
(ii)
$\text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 + \text{KI} \rightarrow$ ______ + ______ + ______ + ______
(iii)
$\text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 + \text{FeSO}_4 \rightarrow$ ______ + ______ + ______ + ______
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Explain why:
(i)
Transition elements form alloys.
(ii)
$\text{Zn}^{2+}$ salts are white whereas $\text{Cu}^{2+}$ salts are coloured.
(iii)
Transition metals and their compounds act as catalyst.
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Explain why:
(i)
$\text{Mn}^{2+}$ is more stable than $\text{Fe}^{2+}$ towards oxidation to $+3$ state. (At. no. of $\text{Mn} = 25$, $\text{Fe} = 26$)
(ii)
Transition elements usually form coloured ions.
(iii)
Zr and Hf exhibit similar properties. (At. no. of $\text{Zr} = 40$, $\text{Hf} = 72$)
No answer yet.
Complete and balance the following chemical equations:
(i)
$\text{KMnO}_4 + \text{KI} + \text{H}_2\text{SO}_4 \rightarrow$ _____ + ______ + ______ + _______
(ii)
$\text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 + \text{H}_2\text{S} \rightarrow$ _____ + ______ + ______ + _______
(iii)
$\text{KMnO}_4 + \text{H}_2\text{SO}_4 + \text{FeSO}_4 \rightarrow$ _____ + ______ + ______ + _______
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Account for the following/Explain why:
(i)
Transition metals exhibit variable oxidation states.
(ii)
$\text{Zr}$ ($Z = 40$) and $\text{Hf}$ ($Z = 72$) have almost identical radii.
(iii)
Transition metals and their compounds act as a catalyst.
No answer yet.
Complete the following chemical equations:
(i)
$\text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 + \text{FeSO}_4 \rightarrow$ _______
(ii)
$\text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 + \text{H}_2\text{S} \rightarrow$ _______
(iii)
$\text{KMnO}_4 + \text{H}_2\text{SO}_4 + \text{H}_2\text{C}_2\text{O}_4 \rightarrow$ _______
No answer yet.