states-of-matter-quiz-5

States of Matter Quiz-5

Dear Readers,

The one subject in NEET which is candidates who can easily attain good marks is Chemistry. That's the reason, often, one doesn’t pay notice and choose to compromise it. But if one wants to rank above others, the tip is to be thorough with NEET chemistry concepts. The understanding of reactions and definite basic understanding is what requires major attention in Chemistry but once done it only gets simpler from there. The main focus on the to-do list should be on getting a hang of the NCERT syllabus of NEET chemistry..

Q1. O₂ is collected over water at 20℃. The pressure inside shown by the gas is 740 mm of Hg. What is the pressure due to O₂ alone if vapour pressure of H₂ O is 18 mm at 20℃ ?

•  722 mm
•  740 mm
•  758 mm
•  None of these

Solution
(a) P_{dry gas}=P_{wet gas}-P_{H2 O}  

Q2.Surface tension of water is 73 dyne cm^-1 at 20℃. If surface area is increased by 0.10 m², work done is

•  7.3 erg
•  7.3×10⁴ erg
•  73 J
•  0.73 J

Solution

(b) Work done = surface tension × increase in area =73 dyne cm^-1×0.10 m² =73 dyne cm^-1×0.10×10⁴ cm² =7.3×10⁴ ergs

Q3. Which is lighter than dry air? 

•  Moist air
•  SO₂
•  Cl₂
•  O₂

Solution
(a) Mol.wt. of moist air is lesser than dry air.

Q4. Which gas is most soluble in water?

•  H₂ S
•  NH₃
•  SO₂
•  CO₂

Solution
(b) Due to H-bonding.

Q5.Total energy of one mole of an ideal gas (monoatomic) at 27℃ is:

•  600 cal
•  900 cal
•  800 cal
•  300 cal

Solution
  (b) KE=3/2 RT=3/2×2×300=900 cal  

Q6. NH₃ and HCl gas are introduced simultaneously from the two ends of a long tube. A white ring of NH₄ Cl appears first

•  Nearer to the HCl end
•  At the centre of the tube
•  Throughout the tube
•  Nearer to the NH₃ end

Solution
(a) White ring of NH₄ Cl will appear nearer to the HCl end. The reason is that HCl (mol. wt. = 36.5) is heavier than NH₃ (mol. wt. Hence, according to Graham’s law of diffusion, the rate of diffusion of NH₃ will be higher than that of HCl.) r₁/r₂ =√(M₂/M₁ )  

Q7.Non-reacting gases have a tendency to mix with each other. This property is known as:

•  Diffusion
•  Fusion
•  Mixing
•  None of these

Solution

(a) Follow diffusion of gases.

Q8.Which gas cannot be kept in a glass bottle because it chemically reacts with glass?

•  F₂
•  Cl₂
•  Br₂
•  SO₂

Solution
(a) F₂ is highly reactive gas.  

Q9.The density of O₂ is 16 at NTP. At what temperature its density will be 14? Consider that the pressure remains constant, at

•  50℃
•  39℃
•  57℃
•  43℃

Solution

(b) d₁ T₁=d₂ T₂ When p remains constant d₁=16;

d₂=14;T₁=273 K,T₂=?

 d₁ T₁=d₂ T₂ 

16×273=14×T₂ 

 T₂=312 K 

 T₂=312-273=39℃

Q10. An open vessel at 27℃ is heated until 3/8th of the air in it has been expelled. Assuming that the volume remains constant, calculate the temperature at which the vessel was heated

•  307℃
•  107℃
•  480℃
•  207℃

Solution

(d) According to Gay Lussac’s law p₁/T₁ =p₂/T₂ 

 If 3th/8 of the air is expelled out then remaining air =5/8 T₂=((273+27)×8)/5 =2400/5=480 K =480-273=207℃