<span>The electronic configuration of cobalt is :1s2 2s2 2p6 3s2 3p6 3d7 4s2 </span>
Acid - base indicators (also known as pH indicators) are substances which change color with pH. They are usually weak acids or bases. you use them if you want to know if a solution is an acid or it it's a base
Explanation:
<em><u>2Al + 2NaOH + 6H2O → 2Na[Al(OH)4] + 3H2</u></em>
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