The second ionisation enthalpies of Li, Be, B and C are in order

• Li > B > C > Be

• Li > C > B > Be

• Be > C > B > Li

• B > C > Be > Li

112.

The ionic species having the largest size is

• Li⁺ (g)

• Rb⁺(aq)

• Li⁺(aq)

• Cs⁺(aq)

The first four ionisation enthalpy values of an element are 191 kcal mol^-1 578 kcal mol^-1 872 kcal mol^-1 and 5962 kcal mol^-1 .The number of valence electrons in the element is

• 1

• 2

• 3

• 4

The ion having the highest mobility in aqueous solution is

• Ba²⁺

• Mg²⁺

• Ca²⁺

• Be²⁺

The main product obtained when a solution of sodium carbonate reacts with mercuric chloride is

• Hg(OH)₂

• HgCO₃HgO

• HgCO₃

• HgCO₃.Hg(OH)₂

Among the alkali metals cesium is the most reactive because :

• its incomplete shell is nearest to the nucleus

• it has a single electron in the valence shell

• it is the heaviest alkali metal

• the outermost electron is more loosely bound than the outer most electron of the other alkali metals

Which of the following pairs of elements cannot form an alloy ?

• Zn, Cu

• Fe, Hg

• Fe, C

• Hg, Na

Which metal has a greater tendency to form metal oxide?

• Cr

• Fe

• Al

• Ca

The correct order in which the first ionisation potential increases is

• Na, K, Be

• K, Na, Be

• K, Be, Na

• Be, Na, K

When carbon monoxide is passed over solid caustic soda heated to 200°C, it forms

• Na₂CO₃

• NaHCO₃

• HCOONa

• CH₃COONa