321.

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

The characteristic not related to alkali metal is

• high ionisation energy

• their ions are isoelectronic with noble gases

• low melting point

• low electronegativity

Generally, the first ionization energy increases along a period. But there are some exceptions. One which is not an exception is

• N and O

• Na and Mg

• Mg and Al

• Be and B

For alkali metals, which one of the following trends is incorrect?

• Hydration energy : Li > Na > K > Rb

• Ionization energy : Li > Na > K > Rb

• Density : Li < Na < K < Rb

• Atomic size : Li < Na < K < Rb

Which one of the following is true?

• NaOH is used in the concentration of bauxite ore

• NaOH is a primary standard in volumetric analysis

• Manganous hydroxide is soluble in excess of NaOH solution

• NaOH solution does not react with Cl

The reaction between sodium and water can be made less vigorous by

• adding a little alcohol

• amalgamating sodium

• adding a little acetic acid

• lowering the temperature