Thermalstability

Question 1

Write the balanced chemical reactions when
i)lithium carbonate is heated
ii)berylium carbonate is heated

Answer 1

i)Li2CO3 —->Li2O + CO2 ( All alkali metal carbonates are thermally stable except Li2CO3
ii)BeCO3 —->BeO + CO2 (BeCO3 is kept in environment of CO2)

Question 2

Write the balanced chemical reactions when
i)LiNO3 is heated
ii)NaNO3 is heated

Answer 2

i)4LiNO3—->2Li2O + 4NO2 + O2
ii)2NaNO3 —->2NaNO2 + O2

generally metal nitrates give metal oxide + NO2 + O2 on decomposition except for Na,K,Rb,Cs

Question 3

Write the balanced chemical reactions when
i)aqueous solution of LiHCO3 is heated
ii)Aqueous solution of NaHCO3 is heated

Answer 3

i)2LiHCO3(aq)—->Li2CO3 + CO2 + H20
ii)NaHCO3(aq)—->NaHCO3(s)
Only Na,K,Rb,Cs bicarbonate exist in solid state

Question 4

Compare thermal stability of:
i) BeO,MgO,CaO,SrO,BaO
ii)BeCO3,MgCO3,CaCO3,SrCO3,BaCO3
iii)LiHCO3,NaHCO3,KHCO3,RbHCO3,CsHCO3

Answer 4

i) BeO>MgO>CaO>SrO>BaO
ii) BeCO3<MgCO3<CaCO3<SrCO3<BaCO3
iii) LiHCO3<NaHCO3<KHCO3<RbHCO3<CsHCO3