If you switched to a 50/50 mixture of ethyl acetate/acetic acid eluent (originally 95% ethyl acetate, 5% acetic acid) the Rf value will increase, decrease or unchanged? Explain your answer briefly.
Here acetic acid is the polar solvent and ethyl acetate somewhat
non-polar and silica gel is also polar.
When polarity of the solvent is 95% ethylacetate and 5%
acetic acid, the Rf value for the polar spot will be very less as
the polar part of the compound binds with silica whereas when
polarity of the solvent is increased the Rf value also increases as
now the polar spot moves upward with the help of the acetic acid or
we can say more distance is covered by the polar spot . For the
non-polar spot the distance will be almost same hence less change
in the Rf value for non-polar spot.
If you switched to a 50/50 mixture of ethyl acetate/acetic acid eluent (originally 95% ethyl acetate,...
1) a. Calculate the pH of a 50:50 buffer mixture of acetic acid and sodium acetate. Calculate percentage ionized for this buffer. b. What if the mixture is 75% acid and 25% conjugate base?
A buffer that is a mixture of acetic acid and potassium acetate has a pH = 5.22. The molar ratio of the conjugate base to weak acid in this buffer is? (acetic acid Ka = 1.8 x 10-5 ) A. 1:3 B. 1:5 C. 3:1 D. 1:1 E. 5:1
3. A constitutional isomer of ethyl acetate has a retention time somewhat less than ethyl acetate itself. Does this alternate isomer have a stronger or weaker intermolecular interaction with the stationary phase of the GC column? Explain briefly. 4. The literature value for the boiling point of ethyl acetate is 77.1 °C at sea level (standard one atmosphere pressure, 101 kPa). A student wished to purify some ethyl acetate while working on a project at the shore of the Dead...
A liquid-phase mixture of 450 mL of acetic acid, 300 mL of ethanol, 2.00 mL of water, and 2.00 mL ethyl acetate are mixed together at 298 K, where the following reaction will occur: CH3COOCH2CH3 +H2O CH3COOH +CH3CH2OH, Kc = 3440 Will the reaction occur from left-to-right or right-to-left (as written)? Please support your answer. (Hints: Can you calculate concentrations of the chemical species initially in appropriate units. Starting with the densities, i.e., specific gravities, and volumes, molar amounts...
Calculate the pH of an acetic acid/acetate buffer in which the concentration of acetic acid is always 0.21 M, but the concentration of sodium acetate (NaCH,COO) corresponds to the following value: 0.63 M. (K, for CH,COOH is 1.8 x 10 5.) Report your answer to three significant figures.
You are making a pH 5.0 buffer with acetic acid (pKa = 4.75) and sodium acetate. You want the total concentration of acetate ([acetic acid] + [sodium acetate] ), to be 0.50 M. What concentrations of acetic acid and sodium acetate do you use to make your buffer? acetic acid sodium acetate
Check Your Learning Ethanol and acetic acid react and form water and ethyl acetate,the solvent responsible for the odor of some nail polish removers. 2 15 When 1 mol each of C2H5OH and CH3CO2H are allowed to react in 1 L of the solvent dioxane, equilibrium is established when mol of each of the reactants remains. Calculate the equilibrium constant for the reaction. (Note: Water is not a solvent in this reaction.)
2. A silica gel TLC plate developed with 5% acetic acid in ethyl acetate is depicted below. Each spot on the plate corresponds to one of the compounds given on the right. Match each spot with a compound. ТСН, H.CO nambumetone ОН a) A=nambutone B= tolmetin C =phenacetin b) A=nambutone B=phenacetin C = tolmetin c) A=phenacetin B= tolmetin C = nambutone A= tolmetin B=phenacetin C = nambutone e) A=phenacetin B=nambutone C = tolmetin tolmetin phenacetin
You have made 1.5 L of buffer by adding just acetic acid and no acetate to a final concentration of 0.300 M. However, you just adjusted the pH of the solution by adding NaOH to a pH of 4.5. The Ka of acetic acid is 1.7*10^-5. What are the new concentrations of acetic acid and acetate?
You perform a fractional distillation of a 100 mL mixture of ethyl acetate (BP 77), toulene (BP 111), and dimethylformamide (BP 153). You monitor the temperature of the vapor, and notice rapid increase in the vapor temperature after 34 mL of distillate, and then again after 89 mL of Distilate. How many mL of Toulene were in the mixture? A. 11 B. 100 C. 55 D.89 E. 34