THE S-BLOCK ELEMENTS Quiz-16

Chemistry Aptitude Quiz

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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. Bleaching action of CaOCl_2 is due to

•  Nascent oxygen
•  Chlorine
•  HClO
•  HCl

Solution
(c)
CaOCl_2+H_2 O→Ca(OH)_2+Cl_2
Cl_2+H_2 O→HClO+HCl

Q2.Ripening of fruits can be carried out in presence of

•  Na_2 SO_4
•  NaCl
•  CaCl_2
•  CaC_2

Solution
(d)
CaC_2+H_2 O→Ca(OH)_2+ CH≡CH
used to ripen fruits

Q3.  Select the correct statement(s)

•  Li_2 CO_3 is only sparingly soluble in water and no LiHCO_3 has been isolated
•  K_2 CO_3 cannot be made by a method similar to the ammonia-soda process
•  Li_2 CO_3 and MgCO_3 both are thermally stable
•  Na_2 CO_3∙NaHCO_3∙2H_2 O is a mineral called trona

Solution
(c)
Li_2 CO_3 and MgCO_3 are decomposed by heating
Li_2 CO_3→Li_2 O+CO_2
MgCO_3→MgO+CO_2

Q4.   The solubilities of carbonates decrease down the magnesium group due to a decrease in

•  Lattice energies of solids
•  Hydration energies of cations
•  Interionic attractions
•  Entropy of solution formation

Solution

Part A

Q5.Which is not the s-block element?

•  [Ar]4s^2 3d^10 4p^6 5s^1
•  1s^2 2s^2 2p^1
•  1s^2 2s^1 2p^1
•  [Ar]4s^1 4p^1

Solution
 (b)
(a) (s-block)
(b) (p-block)
(c) 1s^2 2s^2 in ground state –(s-block) and 1s^2 2s^1 2p^1 in excited state
(d) [Ar]4s^2- ground state
[Ar]4s^1 4p^1- excited state
Thus, s-block

Q6. Bleaching powder loses its power on keeping for a long time because

•  It changes into calcium hypochlorate
•  It changes into calcium chloride and calcium hydroxide
• It absorbs moisturecarbonates
•  It changes into calcium chloride and calcium

Solution
(d)
6CaOCl_2→5CaCl_2+Ca(ClO_3 )_2

Q7.

•  BaCN_2,CaCN_2
•  Ba(CN)_2,Ca(CN)_2
•  Ba(CN)_2,CaCN_2
•  None is correct

Solution
Part C

Q8. Statement 1: S block elements are highly electropositive.
Statement 2: The valance electrons present in s orbital are loosely held.

•  Statement 1 is True, Statement 2 is True; Statement 2 is correct explanation for Statement 1
•  Statement 1 is True, Statement 2 is True; Statement 2 is not correct explanation for Statement 1
•  Statement 1 is True, Statement 2 is False
•  Statement 1 is False, Statement 2 is True

Solution
(a) The loosely held s-electron in the outermost valence shell of these elements makes them, the most electropositive metals which readily give ion’s M^+ or M^(2+).

Q9. Statement 1: Group 1 elements are known as the alkali elements.
Statement 2: S orbital can accommodate only two electrons.

•  Statement 1 is True, Statement 2 is True; Statement 2 is correct explanation for Statement 1
•  Statement 1 is True, Statement 2 is True; Statement 2 is not correct explanation for Statement 1
•  Statement 1 is True, Statement 2 is False
•  Statement 1 is False, Statement 2 is True

Solution
(b)
1. If Assertion is True, Reason is True, Reason is correct explanation of 1
2. If Assertion is True, Reason is True, Reason is not correct explanation of 1
3. If Assertion is True, Reason is False
4. If Assertion is False, Reason is True

Q10. Statement 1: Gypsum is added to cement to increase its rate of setting.
Statement 2: Gypsum is calcium sulphate hemihydrates.

•  Statement 1 is True, Statement 2 is True; Statement 2 is correct explanation for Statement 1
•  Statement 1 is True, Statement 2 is True; Statement 2 is not correct explanation for Statement 1
•  Statement 1 is True, Statement 2 is False
• Statement 1 is False, Statement 2 is True

Solution
(d)
Gypsum is added to coment to decrease its rate of setting.
Gypsum is calcium sulphate dehydrate.

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