The balanced reaction is as follows;
BiCl₂ + Na₂SO₄ --> 2NaCl + BiSO₄
this is a double displacement reaction
the oxidation number of Bi is +2 in both BiCl₂ and BiSO₄
oxidation number of Cl is -1 in both BiCl₂ and NaCl
oxidation number of Na is +1 in both Na₂SO₄ and NaCl
oxidation numbers of elements in SO₄²⁻ remains the same in both compounds.Therefore the oxidation state in any of the elements in the reaction doesn't change. Neither of the elements show an increase or decrease in the oxidation numbers .
Answer for this question is no element decreases its oxidation number.
Answer:The correct answer is option (C).
Explanation:

After the reaction between Zinc and copper(II) chloride, Zinc chloride and copper will be obtained as a product. This reaction occurs because zinc is more reactive than copper which displaces the copper from its aqueous solution.
The student will expect to find copper metal at bottom of the beaker with aqueous solution of zinc chloride.
Hence the correct answer is option (C).
Answer: Luster: Metals are shiny when cut, scratched, or polished.
Malleability: Metals are strong but malleable, which means that they can be easily bent or shaped.
Conductivity: Metals are excellent conductors of electricity and heat.
Explanation: Hope this helped!
Because of its chemical structure.