REDOX REACTIONS Quiz-9

Chemistry Aptitude Quiz

Dear Readers,

IIT JEE exam which consists of JEE Main and JEE Advanced is one of the most important entrance exams for engineering aspirants. The exam is held for candidates who are aspiring to pursue a career in the field of engineering and technical studies. Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything..

Q1. Excess of KI reacts with CuSO_4 solution, and Na_2 S_2 O_3 solution is added to it.Which of the following statements is incorrectfor the reaction?

•  EvolvedI_2 is reduced
•  CuI_2 is formed
•  Na_2 S_2 O_3 is oxidized
•  Cu_2 I_2 is formed

Solution
Part B

Q2.The oxidation number of oxygen in OF_2 is

•  +2
•  -2
•  +1
•  -1

Solution
(a) ∴Oxidation number of O =+2

Q3.  In the reaction 3Br_2+6CO_3^(2-)+3H_2 O⟶5Br^⊖+BrO_3^⊝+6HCO_3^⊝

•  Bromine is oxidized and carbonate is reduced
•  Bromine is reduced and water is oxidised
•  Bromine is neither reduced nor oxidised
•  Bromine is both reduced and oxidised

Solution
(d) It is a disproportionation reaction, and hence,Br_2 is both reduced and oxidized

Q4.  

•  Ring (A) is oxidised
•  Ring (B) is oxidised
•  Both are oxidised
•  None is oxidised

Solution

Q5.Acid-catalysed hydration, oxymercuration-demercu-ration, and hydroboration oxidation reaction will give the same product with:

•  
•  
•  
•  

Solution
  (a) Symmetrical alkenes on acid-catalysed hydration, oxymercuration-demercuration, and HBO reactions give the same product. So the answer is (a)

Q6. 

•  
•  
• 
•  

Solution
(a) The reduction of ArNO_2 group under basic condition with CH_3 ONa or (Na_3 AsO_3+NaOH) or (glucose +NaOH) gives azoxybenzene compound. So the answer is (a)

Q7.The oxidation number of cobalt in K[Co(CO)_4] is

•  +1
•  +3
•  -1
•  -3

Solution
(c)
Oxidation state of Co=-1

Q8.The oxidation number of C in HNC is

•  +2
•  -3
•  +3
•  0

Solution
(a) HNC:1-3+x=0⇒x=2 Oxidation state of C=+2

Q9.Imines or enamines are selectively reduced to 1° or 2° amines with:

•  NaBH_4
•  LAH
•  NaCNBH_3
•  NaAIH_4

Solution
(c) NaCNBH_3 reduces imines or enamines (RCH=NH, or RCH=NH-R^1) or R_2C = NH or R_2 C =NHR') to 1° or 2° amines. So the answer is (c)

Q10. 

•  x=2,y=4
•  x=5,y=3
•  x=3,y=5
• x=4,y=2/>

Solution

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