Question

Which of the following is the strongest oxidising agent : $Cr{O}_4^{2-}Mo{O}_4^{2-},W{O}_4^{2-}.$

Answer 1

Higher the electronegativity, greater the pull on oxidizing agent has for electrons. Higher the pull for electrons, stronger the oxidizing agent.
Here, for $Cr,Mo,W$ down the group, electronegativity increases. So, $W{O}_4^{2-}$ is strong oxidizing agent.