Sodium is a very reactive metal. It is kept in kerosene to prevent it from coming in contact with oxygen and moisture. If this happens, it will react with the moisture present in air and form sodium hydroxide.
Answer:
MPR=90,36%
Explanation:
The recrystallization is a purification process where the solid to purify is dissolved in an appropriated dissolvent and then, changing the conditions the solubility changes and that solid (that was in solution before) precipitates and form crystals.
In this case, for boiling water 5.50 g of acetanilide could be dissolved and then cold the water, so the mass of crystals formed will be

The maximum percent recovery is then

Answer:
Reduction: 2 H⁺(aq) + H₂O₂(aq) + 2 e⁻ ⇒ 2 H₂O(l)
Oxidation: H₂O₂(aq) ⇒ O₂(g) + 2 H⁺(aq) + 2 e⁻
Explanation:
In H₂O₂, hydrogen has the oxidation number +1 and oxygen the oxidation number -1.
In the reduction half-reaction (H₂O₂ is the oxidizing agent), H₂O₂ forms H₂O. The oxidation number of oxygen decreases from -1 to -2.
2 H⁺(aq) + H₂O₂(aq) + 2 e⁻ ⇒ 2 H₂O(l)
In the oxidation half-reduction (H₂O₂ is the reducing agent), H₂O₂ forms O₂. The oxidation number of oxygen increases from -1 to 0.
H₂O₂(aq) ⇒ O₂(g) + 2 H⁺(aq) + 2 e⁻