A compound is known to be Na2CO3, Na2SO4, NaOH, NaCL, NaC2H3O2 or NaNO3-. When barium nitrate solution is added to a solution containing the unknown a white precipitation forms. No precipitate is onserved when a magnesium nitrate solution is added to a solution containing the unknown. What is the identity of the unknown compound? Explain reasoning

- A 0.6842-g sample of potassium hydrogen phthalate was dissolved in 50 mL of deionized water and titrated to a phenolphthalein end- point with 17.28 mL of Ca(OH), solution. What is the molarity of the Ca(OH),?

A titration process is done by using 0.2M of 20 ml of third analytical group main reagent solution with 0.1 M nitric acid solution if nitric acid is replaced by sulphuric acid of same concentration, then the volume of sulphuric acid equals.... a. Half the volume of nitric acid b. Double the volume of nitric acid c. The volume of nitric acid d. Quarter the volume of nitric acid

A 1.2516 gram sample of a mixture of CaCO3 and Na2SO4 was analyzed by dissolving the sample and completely precipitating the Ca2+ as CaC2O4. The CaC2O4 was dissolved in sulfuric acid and the resulting H2C2O4 was titrated with a standard KMnO4 solution. (a)        Write the balanced equation for the titration reaction, shown unbalanced below:                                     MnO4- + H2C2O4 + H+ ® Mn2+ + CO2 + H2O                         (i) Indicate which substance is the oxidizing agent and which substance is the reducing agent. (b)       The titration of the H2C2O4 obtained required 35.62 milliliters of 0.1092 molar MnO4- solution. Calculate the number of moles of H2C2O4 that reacted with the MnO4- (c)        Calculate the number of moles of CaCO3 in the original sample. (d)       Calculate the percentage by weight of CaCO3 in the original sample.