Which one of the following processes will produce hard water?
Solution
Permanent hardness of water is due to chlorides and sulphates of calcium and magnesium i.e CaCl2, CaSO4,MgCl2 and MgSO4.
Philosopher’s wool on heating with BaO at 1100°C produces:
Solution
Estimation of calcium and magnesium is done by
Solution
Calcium and magnesium are estimated by EDTA.
K2CS3 can be called potassium
Solution
In K2CO3 replacement of O by S gives K2CS3 which is called potassium thiocarbonate.
Mixture of MgCl2 and MgO is called :
Solution
Mixture of MgO and MgCl2 is called Sorel’s cement. It is used for making magnesia cement.
Lithopone is
Solution
ZnS + BaSO4 is lithopone. It is used as white pigment.
Amongst LiCl, RbCl,BeCl2 and MgCl2 the compounds with the greatest and least ionic character respectively are :
Solution
According to Fajan's rule,
Size of cation ? Ionic character..
Recall that size of metal (ion) increases while going down the group, and decreases on crossing the periods from left to right.
Thus Rb+(group I) is largest and Be2+(group II) is smallest in size. Hence RbCl has greatest, and BeCl2 has lowest ionic character.
Which of the following compounds is used in preparation of green fire ?
Solution
Ba(NO3)2 is used in preparation of green fire.
The Formula of Mohar’s Salt; FeSO4(NH4)2SO4.XH2O the value of X :
Solution
The Mohr’s salt is represented by the molecular formula FeSO4(NH)2SO4.6H2O
Which one of the following salts does not impart colour to the flame ?
Solution
Halides of group I and II impart characteristic colour to the flame due to low IE of the central atom. However,ionization energy of Be and Mg atoms is high due to their small size, hence they can't be excited to higher levels by Bunsen burner flame. Thus, their halides don't impart colour to flame.
