Hydrogen: chemistry

• Answers are in BOLD Option name.

 Q.1.  When CO  is bubbled through a solution of barium peroxide in water 

A) O is released 

B) Carbonic acid is formed 

C) HO is formed 

D) no reaction occurs 

Explanation-

 

Q.2.  The hydrogen molecule is not very reactive under normal conditions because 

A) Hydrogen has a large number of isotopes 

B) The corresponding  value is very low 

C) The bond dissociation energy of  the hydrogen molecule is high 

D) The hydrogen molecule has a low activation energy 

Explanation-

High bond dissociation energy of hydrogen molecule explains its less reactive nature.

Q.3.  Decomposition of   can be prevented by addition of

A) Acetanilide

B) Benzene

C) Alkali metal oxide 

D) MnO 

Explanation-

Acetanilide acts as stabilizer for .

Q.4. Which is the correct order of boiling point of VA, VIA and VIIA hydride ?

A) 

B) 

C) HF > HI > HBr > HCI

D) All of the above are correct 

Q.5.   HCI is added to following oxides . Which one would give  ?

A) MnO

B) PbO

C) BaO

D) None of the above 

Explanation-

Only peroxides on action of dil. acid gives  

Q.6.  Which of the following ions will cause hardness in water sample ?

A) Na

B) K 

C) Br 

D) Ca 

Explanation-

Soluble Salts of calcium can cause hardness in water.

Q.7.  In context with the industrial preparation of hydrogen from water gas (CO+H) , which of the following is the correct statement ?

A) CO is oxidized to CO with steam in the presence of a catalyst followed by absorption of CO in alkali .

B) CO and H are fractionally separated using differences in their densities.

C) CO is removed by absorption in aqueous CuCl solution .

D) H is removed through occlusion with Pd

Q.8.  A dilute solution of   can be concentrated by 

A) Drying it over anhydrous CaCl

B) Drying it over concentrated HSO

C) Drying it over anhydrous MgSO 

D) Heating it under reduced pressure 

Explanation-

A dilute solution of  can be concentrated by heating (distillation) under reduced pressure.

Q.9. Hydrides of metals are named like 

A) alkane 

B) alkene

C) alkyne

D) None is correct

Q.10. Consider the following statements : 

I : Rate of transfer  of D  from DO  is  slower then that of H b from HO

II :  K for CHCOOH  CHCOO  + H

III : Tritium is a  radioactive isotope . Select the correct statements .

A) I , II 

B) II , III 

C) I , III 

D) I, II , III 

Properties Of Bulk Matter: Physics

• Answers are in BOLD Option name.

Q.1. An iron bar of length l and cross-section A is heated from  If the rod is so held that it is not permitted to expand or bend, the force developed in it is:

A) directly proportional to length

B) inversely proportional to length

C) independent of length

D) inversely proportional to area of cross-section

Explanation-

Change in length 

Stress = 

Clearly F does not depend upon length.

Q.2. The radius of a spherical soap bubble is 0.5 mm. If the surface tension of the soap solution be 30 dyne/ cm, the excess pressure is :

A) 1500 

B) 1000 

C) 2400 

D) 1200 

Explanation-

For soap bubble, excess pressure is 

         

Q.3. A thick rope of rubber of density 1.5 kg/ and  metres in length when hung vertically will increase in length by :

(g=10 m  )

A) 

B) 

C) 

D)  

Explanation-

As the weight of wire is at center of gravity

 

Q.4. The density of ice is x g  and that of water is y g . What is the change in volume when m gram of ice melts ?

A) m ( y - x ) c.c

B) 

C) 

D)  

Explanation-

Vol. of m gram water formed 

Change in vol. on melting 

                       

Q.5. Water rises to a height of 10 cm in capillary tube and mercuy falls to a depth of 3.42 cm in the same tube. If the density of mercury is 13.6 g   and angle of contact is , the ratio of the surface tensions for water and mercury is :

A) 1 : 5.57

B) 1 : 3.57

C) 1 : 6.57

D) 1 : 1.57

Explanation-

 

Q.6. The isothermal bulk modulus of an ideal gas at a pressure P is:

A) P

B) y P

C) P/2

D) P/y

Explanation-

 For isothermal process PV + constant 

Differentiating both sides,

 

Q.7. The reading of a pressure meter attached with a closed water pipe is  On opening the valve, the reading of the pressure meter is reduced to  Calculate the speed of water flowing in the pipe.

A) 10 m/s

B) 20 m/s

C) 30 m/s

D) 40 m/s.

Explanation-

According to Bernoulli's theorem,

   

Q.8. A circular tub filled with liquid is uniformly tapering with base area  and top area  Its depth is 0.4 m as shown in fig. What is the thrust on its base ?  

A) 3.6 N

B) 7.2 N

C) 9 N

D) 14.4 N

Explanation-

Here thrust at bottom 

                      

Q.9. An incompressible liquid flows through a horizontal tube bifurcating at the end as shown

The areas are expressed in  and velocity in . What is the value of  ?

A) 3 

B) 1.5 

C) 1 

D) 1.25 

Explanation-

Here  

Q.10.  A log of wood floats in water with 1/5th of its volume above the surface of water. The density of wood is :

A) 

B) 

C) 

D)  

Explanation-

Here the wt. of the body = Wt. of water displaced by immersed portion of the body