s-block-quiz-6

S-Block Quiz-6

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. Which of the following has the largest size in aqueous solution?

•  Rb⁺
•  Na⁺
•  K⁺
•  Li⁺

Solution
(d) The order of the size of hydrated ions of I group metals is, 

Li⁺ (aq.)>Na⁺ (aq.)>K⁺ (aq.)>Rb⁺ (aq.)>Cs⁺ (aq………….)  

Q2.The characteristic not related to alkali metal is

•  High ionisation energy
•  Their ions are isoelectronic with noble gases
•  Low melting point
•  Low electronegativity

Solution

(a) Alkali metals have low ionisation energy. They posses minimum value of ionisation energy in their period.

Q3. Both Be and Al become passive on reaction with conc. Nitric acid due to: 

•  The non-reactive nature of the metal
•  The non-reactive nature of the acid
•  The formation of an inert layer of oxide on the surface of the metals
•  None of the above

Solution
(c) Both Be and Al are rendered passive due to the formation of inert, insoluble and imprevious oxide layer on their surface.

Q4. Potassium when heated strongly in oxygen, it forms:

•  K₂ O
•  KO₂
•  K₂ O₂
•  KO

Solution
(b) Li forms Li₂ O,Na forms Na₂ O₂ and rest all alkali metals forms superoxides MO₂.

Q5.Black ash is:

•  NaOH+CaS
•  NaHCO₃+CoS
•  Na₂ CO₃+CaS
•  Na₂ CO₃+CoS

Solution
  (c) Black ash is Na₂ CO₃+CaS.  

Q6. Bleaching powder is obtained by the interaction of chlorine and

•  Dry calcium oxide
•  Dry slaked lime
•  conc.solution of Ca(OH)₂
•  dilute solution of Ca(OH)₂

Solution
(b) Ca(OH)₂+Cl₂→ CaOCl₂ +H₂ O bleaching powder  

Q7.Least abundant metal in IIA group is:

•  Sr
•  Ca
•  Ra
•  Be

Solution

(c) Ra is radioactive and thus, decays instantaneously.

Q8.When KCl is heated with conc. H₂ SO₄ and solid K₂ Cr₂ O₇, we get:

•  Chromyl chloride
•  Chromic oxide
•  Chromous chloride
•  Chromic chloride

Solution
(a) 4KCl+6H₂ SO₄+K₂ Cr₂ O₇⟶2CrO₂ Cl₂+6KHSO₄+3H₂ O  

Q9.A and B are two salts. A with dilute HCl and B with conc. H₂ SO₄ react to give reddish brown vapours, hence A and B respectively are:

•  NaBr,NaNO₃
•  NaNO₃,NaBr
•  NaBr,NaNO₂
•  NaNO₂,NaBr

Solution

(d) NaNO₂ gives NO₂(brown) with dil. Acids whereas NaBr and NaNO₂ both give brown vapours Br₂ and NO₂ respectively with conc. acids.

Q10. Slaked lime is:

•  CaCO₃
•  CaO
•  Ca(OH)₂
•  Ca(C₂ O₄)

Solution

(c) White wash in our houses is made by slaked lime, Ca(OH)₂.