United States or Pakistan ? Vote for the TOP Country of the Week !
A chemist received four different solutions, with the statement that they contained either pure NaOH; pure Na CO ; pure NaHCO , or mixtures of these substances. From the following data identify them: Sample I. On adding phenolphthalein to a solution of the substance, it gave no color to the solution.
Weight of sample 1.000 gram; volume of 0.25 N hydrochloric acid required for phenolphthalein end-point, 26.40 cc.; after adding an excess of acid and boiling out the carbon dioxide, the total volume of 0.25 N hydrochloric acid required for phenolphthalein end-point, 67.10 cc. !Answer!: 69.95% Na CO ; 30.02% NaHCO .
But we must observe that with these dibasic acids it is possible, by adding insufficient alkali to completely saturate them, to obtain salts in which only one hydrogen atom of the acid is replaced by the metal of the base. Thus sulphuric and carbonic acids yield NaHSO , acid sulphate or bisulphate of soda, and NaHCO , bicarbonate of soda, respectively.
!Answers!: 24.50% NaOH; 64.92% Na CO . From the following data, calculate the percentages of Na CO and NaHCO in an impure mixture.
Word Of The Day