<p>A metal oxide has the formula&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>Z</mi><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></math>. It can be reduced by hydrogen to give free metal and water.0.1596g of the metal oxide requires 6 mg of hydrogen for complete reduction. The atomic mass of the metal is:</p>