# In acidic medium, $H_2O_2$ changes $Cr_2 O_7^{-2}$ to $CrO_5$ which has two $(- O - O - )$ bonds Oxidation state of $Cr$ in $CrO_5$ is :
( A ) $+6$
( B ) $+5$
( C ) $+3$
( D ) $-10$