s-block-quiz-7

S-Block Quiz-7

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. When CO₂ is bubbled into an aqueous solution of Na₂ CO₃, the following is formed:

•  H₂ O
•  OH^-
•  NaHCO₃
•  NaOH

Solution
(c) Na₂ CO₃+CO₂+H₂ O⟶2NaHCO₃  

Q2.Washing soda is:

•  Na₂ CO₃
•  Na₂ CO₃∙H₂ O
•  Na₂ CO₃∙7H₂ O
•  Na₂ CO₃∙10H₂ O

Solution

(d) Washing soda is chemically Na₂ CO₃∙10H₂ O.

Q3. Ca,Sr and Ba dissolve in liquid ammonia giving a…… 

•  Highly conducting
•  Highly reducing
•  Paramagnetic
•  All are correct

Solution
(d) All are fact. It is the ammonia solvated electron (NH₃ )_x.e responsible for these properties.

Q4. How many elements are included in IA group?

•  4
•  5
•  6
•  7

Solution
(c) Li,Na,K,Rb,Cs,Fr are I group members.

Q5.Which one of the following substances is used in the laboratory for a fast drying of neutral gases?

•  Phosphorus pentoxide
•  Active charcoal
•  Anhydrous calcium chloride
•  Na₃ PO₄

Solution
  (c) Anhydrous CaCl₂ is used for fast drying of neutral gases.  

Q6. When KI is added to acidified solution of sodium nitrite then

•  NO gas is liberated and I₂ is set free
•  N₂ gas is liberated and HI is produced
•  N₂ O gas is liberated and I₂ is set free
•  N₂ gas is liberated and HOI is produced

Solution
(a) When KI is added to acidified solution of sodium nitrite NO gas is liberated and I₂ is set free. 

 2I^-+4H⁺+2NO₂^- ⟶2NO+I₂+2H₂ O  

Q7.Which gives least basic oxide?

•  Mg
•  Ba
•  Be
•  Ra

Solution

(c) The basic character of metal oxides and hydroxides decreases along the period and increases down the gp

Q8.Which of the following will liberate hydrogen by its reaction with hydrochloric acid?

•  Copper
•  Phosphorus
•  Mercury
•  Magnesium

Solution
(d) Mg+2HCl⟶MgCl₂+H₂ ; E_(OPMg)>E_(OPH)  

Q9.The chloride ion is isoelectronic with potassium. The size of chloride ion is:

•  Larger than K⁺ion
•  Smaller than K⁺ ion
•  Same as that of K⁺ ion
•  None of these

Solution

(a) Effective nuclear charge (ENC) of K⁺>ENC of Cl^- and thus, shells are pulled more effectively in K⁺ ion.

Q10. Beryllium hydride is obtained by:

•  Heating Be in atmosphere of H₂
•  The action of BeCl₂ with LiAIH₄
•  The action of Be with CaH₂
•  None of the above

Solution

(b) Hydrides of alkaline earth metals (except Be) are obtained by heating them in hydrogen. BeH₂ is obtained by 2BeCl₂+LiAlH₄⟶2BeH₂+LiCl+AlCl₃