S-Block

Question 1

Ions found in biological fluids

Answer 1

Na, K, Mg, Ca

Question 2

Order of density of alkali metals

Answer 2

Li<K<Na<Rb<Cs [Density]

Question 3

what colour does Li shows to an oxidizing flame

Answer 3

Crimson red

Question 4

what colour does Na shows to an oxidizing flame

Answer 4

yellow

Question 5

what colour does K shows to an oxidizing flame

Answer 5

Violet

Question 6

what colour does Rb shows to an oxidizing flame

Answer 6

Red violet

Question 7

what colour does Cs shows to an oxidizing flame

Answer 7

Blue

Question 8

Li + O2 mainly forms

Answer 8

Li2O (oxide)

Question 9

Na+O2 mainly form

Answer 9

Na2O2 (peroxide)

Question 10

M(K/Rb/Cs) + O2 mainly forms

Answer 10

MO2 (superoxide)

Question 11

Which metals react with Nitrogen from air to form MN3 (nitride)

Answer 11

LiN3

Question 12

Which metal is covered with Paraffin wax instead of keeping it submerged in kerosene to prevent oxidation

Answer 12

Li

Question 13

Alkali metals(M) reacts with water to form

Answer 13

MOH + H2(g)

Question 14

Does Li reacts with C2H2

Answer 14

no

Question 15

Does Na reacts with C2H2

Answer 15

yes

Question 16

Li reacts with ammonia to form

Answer 16

Li2NH(Lmide) + dihydrogen gas

Question 17

are alkali metal hydrides are ionic compound

Answer 17

yes

Question 18

are alkali metal hallides are ionic

Answer 18

yes

Question 19

Among Hallides, which Li hallide is the most covalent in nature

Answer 19

LiI

Question 20

Order of Reducing power of alkali powers

Answer 20

Na<K<Rb<Cs<Li

Question 21

What happens when alkali metals are dissolved in water for a long period of time.What colour did it change and is it dimagnetic or paramagnetic

Answer 21

Deep blue colour to Bronze colour, Dimagnetic

Question 22

why does it gives deep blue colour when alkali metals are dissolved in liquid ammonia

Answer 22

Ans – Ammoniated electron
it form ammoniated cation and anion, and ammoniated electron is responsible for this colour change

Question 23

Li2O + water –> ?

Answer 23

LiOH

Question 24

Na2O2 + water –> ?

Answer 24

NaOH + H2O2

Question 25

K/Rb/CsO2 + water --> ?

Answer 25

K/Rb/csOH + H2O2 + O2

Question 26

Colour of pure oxides and peroxies

Answer 26

Colourless

Question 27

Colour of superoxides and is it paramagnetic or diamagnetic

Answer 27

yellow/ orange, paramagnetic

Question 28

hydroxides obtained from oxide + H20 are in which colour and is it amorphous or crystalline

Answer 28

white crystalline

Question 29

Alkali metals halids can be prepared by the reaction of?

Answer 29

alkali hydroxides, oxides / carbonate with Hydrohaulic acids

Question 30

Low solubility of Lif in water is due to

Answer 30

High latice energy

Question 31

Low solubility of CsI in water is due to

Answer 31

low hydration energy

Question 32

MCl is soluble in pyridine, what is M

Answer 32

Li

Question 33

which hydrocarbonate doesnt exist in solid, but does in aq soln

Answer 33

Li bicarbonate