Correct Answer - C
`6 mmol Br_(2)-=2 mmol Br_(3)^(ɵ)`
`(36xx0.5)=(1)/(3)xx36xx0.5 mmol BrO_(3)^(ɵ)`
`BrO_(3)^(ɵ)+3As^(3+)+6H^(o+)toBr^(ɵ)+3As^(5+)+3H_(2)O`
`1 m" mol of "BrO_(3)^(ɵ)-=3 mmol As^(3+)`
`6.0 mmol BrO_(3)^(ɵ)-=mmol As^(3+)`
`(MAs^(3+)=(18)/(45)=0.4M)`