could i use l293d to interface MCU to separate relays?
do i need external freewheeling diodes ?
is there any problem with this circuit

 

Circuit looks OK to me. One issue might be the Vcc2 supply. The high level output from the L293 will be less then the supply voltage so might be a problem with the relays.
If necessary you could raise the Vcc supply a bit to compensate.
SG

 

Yes, the circuit should work quite well if the relay coil currents ar not excessively high.

 

relays are working on 5 v, so does the l293d.
if the supply vcc is 5 v , what is the expected output to the relay?

 

relays are working on 5 v, so does the l293d.
if the supply vcc is 5 v , what is the expected output to the relay?

The relay voltage depends on the relay current, and if the relays draw 50 mA then the voltage should be at least 4.8 volts. Since the usual tolerance on relay voltages is 10%, it should work out very well.

 

voltage should be at least 4.8 volts.

I think it will be a maximum of 4.3 volts from looking at the output of the L293D.
You can also remove the diodes across the relay coils as they are included in the L293D
SG