S-Block Flashcards
Ions found in biological fluids
Na, K, Mg, Ca
Order of density of alkali metals
Li<K<Na<Rb<Cs [Density]
what colour does Li shows to an oxidizing flame
Crimson red
what colour does Na shows to an oxidizing flame
yellow
what colour does K shows to an oxidizing flame
Violet
what colour does Rb shows to an oxidizing flame
Red violet
what colour does Cs shows to an oxidizing flame
Blue
Li + O2 mainly forms
Li2O (oxide)
Na+O2 mainly form
Na2O2 (peroxide)
M(K/Rb/Cs) + O2 mainly forms
MO2 (superoxide)
Which metals react with Nitrogen from air to form MN3 (nitride)
LiN3
Which metal is covered with Paraffin wax instead of keeping it submerged in kerosene to prevent oxidation
Li
Alkali metals(M) reacts with water to form
MOH + H2(g)
Does Li reacts with C2H2
no
Does Na reacts with C2H2
yes
Li reacts with ammonia to form
Li2NH(Lmide) + dihydrogen gas
are alkali metal hydrides are ionic compound
yes
are alkali metal hallides are ionic
yes
Among Hallides, which Li hallide is the most covalent in nature
LiI
Order of Reducing power of alkali powers
Na<K<Rb<Cs<Li
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
Deep blue colour to Bronze colour, Dimagnetic
why does it gives deep blue colour when alkali metals are dissolved in liquid ammonia
Ans – Ammoniated electron
it form ammoniated cation and anion, and ammoniated electron is responsible for this colour change
Li2O + water –> ?
LiOH
Na2O2 + water –> ?
NaOH + H2O2
K/Rb/CsO2 + water –> ?
K/Rb/csOH + H2O2 + O2
Colour of pure oxides and peroxies
Colourless
Colour of superoxides and is it paramagnetic or diamagnetic
yellow/ orange, paramagnetic
hydroxides obtained from oxide + H20 are in which colour and is it amorphous or crystalline
white crystalline
Alkali metals halids can be prepared by the reaction of?
alkali hydroxides, oxides / carbonate with Hydrohaulic acids
Low solubility of Lif in water is due to
High latice energy
Low solubility of CsI in water is due to
low hydration energy
MCl is soluble in pyridine, what is M
Li
which hydrocarbonate doesnt exist in solid, but does in aq soln
Li bicarbonate
