Question

For the following chemical reactions, which is (are) Redox reactions? For the redox reaction, sketch how oxidation number change, and which is reduced and which is oxidized?

1) Zn +2HCl(aq) = ZnCl2 (aq) + H2

2) CaCl2 (aq) + Na2CO3 (aq) = CaCO3 (s) +2 NaCl (aq)

3) NH3 (aq) + HCl (aq) = NH4Cl (aq)

4) C8H18 ( gasoline) +25/2 O2 = 9H2O + 8CO2 (g)

5) To prepare 500ml 1.0M HNO3, how much 3.0M HNO3 is required and how much water should be added?

Answer 1

Answer:

NaOH(aq) + NH4Cl(aq) NaCl(aq) + NH3(aq) + H2O(l) ... Reactions that involve a transfer of electrons are known as oxidation-reduction or ... In an oxidation- reduction reaction, at least two oxidation numbers change.

Answer 2

Answer:

Concept:

Redox reactions are oxidation-reduction chemical processes in which the oxidation states of the reactants change. Redox is a shortened version of reduction-oxidation. Two distinct processes—a reduction process and an oxidation process—can be used to describe all redox reactions.

Explanation:

1) $\mathrm{Zn}+2 \mathrm{HCl} \rightarrow \mathrm{ZnCl}_{2}+\mathrm{H}_{2} \uparrow$

Displacement reaction

Displacement reactions occur when one reactive element in the solution is replaced by another. In this instance, hydrogen from HCl is being replaced by zinc. So, this serves as an illustration of a displacement response.

2) $\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq})+\mathrm{CaCl}_{2}(\mathrm{aq}) \rightarrow \mathrm{CaCO}_{3}(\mathrm{~s})+2 \mathrm{NaCl}(\mathrm{aq})$

Double Displacement reaction

When two soluble ionic compounds combine to create an insoluble ionic compound, a gas, or a slightly ionized chemical, this reaction is known as a twofold displacement or metathesis reaction. We'll examine a reaction that results in the formation of a precipitate. AB + CD ---->  CB + AD is the generic formula for this reaction, where A and C are cations and B and D are anions.

3) $\mathrm{NH}_{3}+\mathrm{HCl} \rightarrow \mathrm{NH}_{4} \mathrm{Cl}$

Synthesis reaction

4) $\mathrm{C}_{8} \mathrm{H}_{18}(\mathrm{~g})+\frac{25}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 8 \mathrm{CO}_{2}(\mathrm{~g})+9 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})$

Exothermic reaction

For combustion, heat is always liberated. i.e. it is an exothermic reaction.

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