If anyone can please help me and give me explanations... I\'d be thankful and wi
ID: 630925 • Letter: I
Question
If anyone can please help me and give me explanations... I'd be thankful and will give 5 stars.
(1) Which of the following has the highest boiling point?
a) 1-chloropentane
b) 2-pentanol
c) pentanoic acid
d) pentane
(2) Which of the following is not true regarding carboxylic acids?
a) the carbon-oxygen bonds of the formate anion (HCOO-) are the same lenght.
b) carboxylic acids are almost completely dissociated in water.
c) carboxylic acids with five or fewer carbon atoms quite water-soluble.
d) the carbon atom of formic acid, HCOOH, is sp2 hybridized.
(3) Which of the following is not true?
a) The value of the acidity constant, Ka, for an acid dissolved in water is given by: Ka = [RCOO-][H#O+]/[RCOOH][H2O]
b) Alkali metal salts of low molecular weight carboxylic acids are generally quite soluble in wate.
c) carboxylic acids are much weaker acids than HCl.
d) resonance stabilization of the carboxylate anion helps to explain the greater acidity of carboxylic acids than alcohols.
(4) Which of the following does not have the compounds in order of decreasing acid strength (more acidic > less acidic)?
a) CF3COOH > CH2FCOOH > CH3COOH
b) CF3COOH > CH2ClCOOH > CH2COOH
c) CH3COOH > CH3CH2OH > CH3CH3
d) ClCH2CH2COOH > CH3CHClCOOH > CH3CH2COOH
(5) Which of the following is the strongest acid?
a) benzoic acid
b) 4-nitrobenzoic acid
c) 4-methylbenzoic acid (toluic acid)
d) 4-methyoxybenzoic aid
(6) What is the approximate range of chemical shifts in the 13C NMR spectrum for the carboxyl carbon atom of carboxylic acids?
a) 100-140 ppm
b) 160-180 ppm
c) 180-220 ppm
d) 20-60 ppm
(7) What is the approximate range of chemical shifts in the 1H NMR spectrum for the acidic proton of carboxylic acids?
a)2-4 ppm
b) 10-12 ppm
c) 6-8 ppm
d) 0-2 ppm
Explanation / Answer
1-c (H bonding more in acid) , 2- b( COOH are not strong acids), 3- a ( in K expresion H2O is not involved since H2O is liq), 4- d ( Cl close to COOH is more acidic but it was placed middle in order), 5- b ( NO2 is electron with drwaing and hence delocalises _ ve charge after H+ elimination), 6-b , ( due to Electro negative nature of adjacent O , C13 NMr peak downfileds) 7- b ( due to high deshileding produced by local electron current)