SOME BASIC CONCEPTS OF CHEMISTRY Quiz-9

 

SOME BASIC CONCEPTS OF CHEMISTRY Quiz-9

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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.The concentration of 10% CH_3 COOH in mol L^(-1) is :

•  10
•  0.83
•  1
•  1.67

Solution

Q2.KCl+conc.H_2 SO_4+K_2 Cr_2 O_7 □(→┴( ∆ ) ) (X) □(→┴( NaOH ) ) (Y).(X) is reddish brown coloured gas soluble in NaOH forming (Y),(X) and (Y) are

•  Cr_2 OCl_2,Na_2 CrO_3
•  Cr_2 O_2 Cl_2,Na_2 CrO_3
•  CrO_2 Cl,Na_2 CrO_4
•  CrO_2 Cl_2,Na_2 CrO_4

Solution

Q3.In the titration of 100 mL of 0.01 M CH_3 COOH with 0.01 M NaOH,[H_3 O^+ ]=K_awhen  

•  100 mL of NaOH has been added
•  75 mL of NaOH has been added
•  50 mL of NaOH has been added
•  25 mL of NaOH has been added

Solution

Q4.By H_2 O_2/OH^-,Cr(OH)_3 changes to 

•  CrO_3
•  Cr_2 O_7^(2-)
•  CrO_4^(2-)
•  [Cr(OH)_4 ]^-

Solution

Q5.800 g of a 40% solution by weight was cooled. 100 g of solute precipitated. The percentage composition of remaining solution is

•  

  31.4%

•  20.0%
•  23.0%
•  24%

Solution
 

Q6.The purity of H_2 O_2 in a given sample is 85%. Calculate the weight of impure sample of H_2 O_2 which requires 10 mL of M/5 KMnO_4 solution in a titration in acidic medium

•  2 g
•  0.2 g
• 0.17
•  0.15 g

Solution

 

Q7.A is a colourless substance. Aqueous solution of A gives reddish-orange ppt with KI; ppt dissolves in excess of KI forming a colourless solution. If NH_4 Cl and NaOH solution is added to this colourless solution reddish brown ppt is formed. Substance A is

•  Epsom salt
•  Mohr’s saslt
•  Calomel
•  Corrosive sublimate

Solution
OPTION D

Q8.K_4 [Fe(CN)_6] can be used to detect some ions out of Cd^(2+),Cu^(2+),Zn^(2+),Fe^(3+),Pb^(2+) and Bi^(3+). Exclude ions are

•  Fe^(3+),Bi^(3+),Pb^(2+)
•  Cu^(2+),Zn^(2+),Bi^(3+)
•  Bi^(3+),Pb^(2+)
•  Fe^(3+),Pb^(2+)

Solution
OPTION C

Q9. In the estimation of nitrogen by Kjeldahl’s method, 2.8 g of an organic compound required 20 millimoles of H_2 SO_4 for the complete neutralisation of NH_3 gas evolved. The percentage of nitrogen in the sample is

•  20%
•  10%
•  40%
•  30%

Solution

Q10. Mixture of 1 mole of Na_2 CO_3 and 2 moles of NaHCO_3 forms 1 mole of CO_2. Thus, per cent yield of CO_2 is  

•  25%
•  50%
•  75%
• 100%

Solution

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