Question

Q1: Write the balanced molecular reaction and the net ionic reaction for the reaction between BaCl2 and Na3PO4 in aqueous solution: Molecular reaction:

____BaCl2(aq) + ____Na3PO4(aq) → ____ ___________ + ____ __________

Net ionic reaction:

Q2: Classify the following reactions as: acid-base, precipitation, combustion, combination, and displacement or disproportionation reaction:

BaCl2(aq) + MgSO4(aq) → BaSO4(s) + MgCl2(aq) __________________________ reaction

NH3(aq) + HBr(aq) → NH4Br(aq) _______________________________

reaction 2CO(g) + O2 → 2CO2(g) _______________________________ reaction

Q3: Circle the correct answer for each

            CO3^2– is a                    Brønsted acid / Brønsted base / can be both

            HCO3^– is a                  Brønsted acid / Brønsted base / can be both

            PO4^3– is a                    Brønsted acid / Brønsted base / can be both

            H3PO4 is a                   Brønsted acid / Brønsted base / can be both

            H2PO4^– is a                 Brønsted acid / Brønsted base / can be both

            CH3COOH is a           Brønsted acid / Brønsted base / can be both

            CH3COO^– is a             Brønsted acid / Brønsted base / can be both

            SO4^2– is a                     Brønsted acid / Brønsted base / can be both

Q4: The oxidation numbers of S in SO3^2– and,SO4^2– are:

A. +2 and + 4              B. +3 and +6               C. +4 and +6               D. +6 and +8               E. –4 and –6

Q5: The oxidation number of Cr in the dichromate ion, Cr2O7^2– is:

A. +6                           B. +5                           C. +4                           D. –4                           E. +7

Q6 For which of the following pairs are both compounds insoluble in water?

A.NaBr, Na2SO4

B. Na2CO3, CaCO3  

C. Fe2(CO3)3, Ba3(PO4)2

D. Na3PO4, Ca3(PO4)2

E. PbSO4, MgSO4

Answer 1

3BaCl2 + 2Na₃PO4 ---->Ba₃(PO4)2 + 6NaCl

3Ba⁺² +6Cl-+ 2PO4-2 + 6Na+ -----> Ba3(PO4)2 +6Na+ 6Cl-

net onic equation 3Ba⁺² + 2PO4^{-2 -}----> Ba3(PO4)2

2. BaSO4 gets precipitated. Hence precipitation reaction

3. NH3 (base)+ HBr( acid) ----> NH4Br acid base reaction

4. 2CO+ O2----> 2CO2 is combustion reaction.

5he

Brønsted-Lowry definition of an acid is a substance capable of donating a proton (H + ), and a base

is a substance capable of accepting a proton

5. CO32- is base. As it cant donate any proton(i.e hydrogen ions).

6. HCO3- is conjugate base of H2CO3   but it can donoate H+ and becomes CO3-2. Hence it is an acid as well as base.

6. PO4-3 is base

7. H3PO4 is acid

8. H2PO4- is acid as well as base. since it can loose proton and also accepts proton to become H3PO4.

9. CH3COOH is acid

10. CH3COO- is base.

11. SO4-2 is base.

12.   3 oxygen atoms are there and hence total charge is -6 and there is -2 charge on SO4-2

x-6= -2 x=4   similarly for SO4-2 = x-8= -2 x= 6 so oxidation numbers are +4 and +6

13.x*2+2*(-7)= -2

x=6 the oxidation number of chromium ins Cr2O7-2 is +6

14. Fe2(CO3)3 and Ba3(PO4)2 are insoluble in water.

6.