Which zone of the blast furnace has the highest temperature?

The correct statement regarding the given Ellingham diagram is

$FeCr_2O_4$ (chromite) is converted to $Cr$ by following steps:
Chromite $\xrightarrow{I} Na_2CrO_4$ $\xrightarrow{II} Cr_2O_3$ $\xrightarrow{III} Cr$
Reagents in $I, II$ and $III$ steps might be:
$I$ Step $-$ $II$ Step $-$ $III$ Step

Which of the following is an acidic flux?

The reaction for obtaining the metal $(M)$ from its oxide $(M_{2}O_{3})$ ore is given by
$M_{2}O_{3(s)} + 2 Al(\ell) \xrightarrow{\text{Heat}} Al_{2}O_{3}(\ell) + 2 M_{(s)}$, $(s = \text{solid}, \ell = \text{liquid})$
In this case, $M$ is

In the process of extracting chromium and manganese metals from their oxides (Alumino-thermite process),aluminum is used as a ...... .