A mixture of hydrazine and 40 to 60 per cent of H₂O₂ solution is:

A mixture of hydrazine and 40−60 percent H₂​O₂​ solution is used as rocket fuel. 

The single bond between the two oxygen atoms in H₂​O₂​ is weak so that, H₂​O₂​ readily fragments into either H and HO₂​ or two OH radicals. Either way, the resulting species are free radicals, which means, they are very reactive and this makes H₂​O₂​ a very powerful oxidizing agent. 

Due to this reason, it has been utilized in rocket propulsion, when it is used to oxidize the hydrazine fuel, liberating hot gases (steam and oxygen), which propels the rocket forward.