Question

Hydrogen peroxide, H2O2, decomposes to water and oxygen gas. What is the oxidation state (oxidation number) for oxygen in hydrogen perioxide?

+1

+2

-1

-2

0 What volume of 0.10 M CH3CO2H is required to react with 0.50 moles of NaHCO3 in the following reaction? The balanced equation is: CH3CO2H(aq) + NaHCO3(s)  → CO2(g) + H2O(l) + NaCH3CO2(aq) 1.0 L 2.0 L 0.50 L 5.0 L 0.20 L

If 23.6 mL of 0.200 M NaOH is required to neutralize 10.00 mL of a H3PO4 solution , what is the concentration of the phosphoric acid solution?

Start by balancing the equation for the reaction:  

H3PO4(aq) + NaOH(aq)  → Na3PO4(aq) + H2O(l)

0.472 M

1.42 M

0.157 M

0.282 M

0.0667 M

Answer 1

1. 2H2O2(aq) -------------->2H2O(l)   + O2(g)

in H2O2 oxygen oxidation state is -1.

H-O--O-H peroxy bond. In peroxides oxygen oxidation state is -1

-1>>>>answer

2.

CH3CO2H(aq) + NaHCO3(s)  → CO2(g) + H2O(l) + NaCH3CO2(aq)

1 mole of NaHCO3 react with 1 mole of CH3CO2H

0.5 moles of NaHCO3 react with 0.5 moles of Ch3CO2H

no of moles of CH3CO2H   = molarity * volume in L

0.5                                       = 0.1* volume in L

volume in L                           = 0.5/0.1 = 5 L

5.0L >>>>>answer

3.

H3PO4(aq) + 3NaOH(aq)  → Na3PO4(aq) + 3H2O(l)

1 mole         3 moles

H3PO4                                                        NaOH

M1 =                                                          M2 = 0.2M

V1 = 10ml                                                  V2 = 23.6ml

n1 = 1                                                        n2 = 3

                 M1V1/n1    =    M2V2/n2

                       M1         =   M2V2n1/V1n2

                                      =   0.2*23.6*1/10*3    = 0.157M

The concentration of the phosphoric acid solution is 0.157M

0.157M >>>>.answer