Question

Deduce the molecular formula of the compound obtained from the following
pairs of elements by the cross multiplication method.
a) N (Valency 3) & H(Valency 1)
b) C (Valency 4) & O(Valency 2)
c) Ca (Valency 2) &O(Valency 2)

Answer 1

Answer:

N (Valency 3) & H(Valency 1)

here N -3. and. H +1

\ /

/ \

NH3

According to the cross multiplication method,

formula of molecular compound is NH3.

which is ammonia.

C (Valency 4) & O(Valency 2)

Here C 4. and O -2

\ /

/ \

C2O4

According to the cross multiplication method,

formula of molecular compound is C2O4

which is oxalate.

Ca (Valency 2) &O(Valency 2)

Here Ca +2 and O -2

\ /

/ \

Ca2O2

=> CaO

According to the cross multiplication method,

the valencies of both calcium and oxide are same so it gets cancelled.So we get the formula as:

of molecular compound is CaO

which is Calcium oxide.

Hope it helps ☺️

Answer 2

Answer:

N (Valency 3) & H(Valency 1)

here N -3. and. H +1

\ /

/ \

NH3

According to the cross multiplication method,

formula of molecular compound is NH3.

which is ammonia.

C (Valency 4) & O(Valency 2)

Here C 4. and O -2

\ /

/ \

C2O4

According to the cross multiplication method,

formula of molecular compound is C2O4

which is oxalate.

Ca (Valency 2) &O(Valency 2)

Here Ca +2 and O -2

\ /

/ \

Ca2O2

=> CaO

According to the cross multiplication method,

the valencies of both calcium and oxide are same so it gets cancelled.So we get the formula as:

of molecular compound is CaO

which is Calcium oxide.

Explanation: