Question

what is the name of 6th factor which is unwanted for clotting of blood

Answer 1

there is no sixth factor ......Actually, there was a sixth factor. Later it was found that, what they called as Factor VI is really activated Factor V.

Hence it is more correct to call it as Va, instead of VI. Factor V is proaccelerin. Hence factor VI or Va is accelerin.

Answer 2

There is no clotting factor assigned as number 6...

the space has been left for it without disturbing the sequence of 12 blood clotting factors...