Class 12 Chemistry CBSE D&F Block Board Questions
Here we provide Class 12 chemistry important notes,board questions and predicted questions with Answers for chapter D&F Block. These important notes,board questions and predicted questions are based on CBSE board curriculum and correspond to the most recent Class 12 chemistry syllabus. By practising these Class 12 materials, students will be able to quickly review all of the ideas covered in the chapter and prepare for the Class 12 Board examinations as well as other entrance exams such as NEET and JEE.
2020
Q1
Write the balanced chemical equation involved in the preparation of KMnO4 from pyrolusite
ore (MnO2)
solutions
solutions
OR
Q2
Write the balanced ionic equations showing the oxidising action of acidified dichromate
(Cr2O2-7) solution with
(i) iron (II) ion
(ii) tin (II) ion
solutions
(i) iron (II) ion
(ii) tin (II) ion
solutions
2019
Q3
Give reason for the following:
(i) Transition elements and compounds act as catalyst.
(ii) Eo value for(Mn2+| Mn) is negative whereas for (Cu2+ | Cu) is positive.
(iii) Actinoids show irregularities in their electronic configuration
solutions
(i) Transition elements and compounds act as catalyst.
(ii) Eo value for(Mn2+| Mn) is negative whereas for (Cu2+ | Cu) is positive.
(iii) Actinoids show irregularities in their electronic configuration
solutions
2017
Q4
(a) Account for the following:
(i) Transition metals show variable oxidation states
(ii) Zn Cd and Hg are soft metals.
(iii)Eo value for the Mn3+/ Mn2+ couple is highly positive (+1.57 V) as compared to Cr3+/ Cr2+
(b) Write one similarity and one difference between the chemistry of lanthanoide and actinoid elements.
solutions
(i) Transition metals show variable oxidation states
(ii) Zn Cd and Hg are soft metals.
(iii)Eo value for the Mn3+/ Mn2+ couple is highly positive (+1.57 V) as compared to Cr3+/ Cr2+
(b) Write one similarity and one difference between the chemistry of lanthanoide and actinoid elements.
solutions
OR
Q5
(a) Following are the transition metal ions of 3d series :
Ti4+, V2+ , Mn3+, Cr3+
(Atomic numbers : Ti=22, V=23, Mn=25, Cr=24)
Answer the following:
(i) Which ion is most stable in an aqueous solution and why?
(ii) Which iron is a strong oxidising agent and why?
(iii) Which ion is colourless and why?
(b) Complete the following equations:
solutions
Ti4+, V2+ , Mn3+, Cr3+
(Atomic numbers : Ti=22, V=23, Mn=25, Cr=24)
Answer the following:
(i) Which ion is most stable in an aqueous solution and why?
(ii) Which iron is a strong oxidising agent and why?
(iii) Which ion is colourless and why?
(b) Complete the following equations:
solutions
2016
Q6
(a) Account for the following :
(i) Mn shows the highest oxidation state of +7 with oxygen but with fluorine it shows the highest oxidation state of +4
(ii) Cr2+ is a storng reducing agent.
(iii) Cu2+ salts are coloured while Zn2+ salts are white.
(b) Complete the following equations :
solutions
(i) Mn shows the highest oxidation state of +7 with oxygen but with fluorine it shows the highest oxidation state of +4
(ii) Cr2+ is a storng reducing agent.
(iii) Cu2+ salts are coloured while Zn2+ salts are white.
(b) Complete the following equations :
solutions
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