A compound A has prominent infrared absorptions at 1050, 1786, and 1852 cm–1 and shows a single absorption in the proton NMR spectrum at δ 3.00. When heated gently with methanol, compound B, C5H8O4, is obtained. Compound B has IR absorptions at 2500–3000 (broad), 1730, and 1701 cm–1, and its proton NMR spectrum in D2O consists of resonances at δ 2.7 (complex splitting) and δ 3.7 (a singlet) in the intensity ratio 4:3. Give the structures A and B, omitting stereochemistry.

Compound A is succinic anhydride and B is methyl succinate (the monomethyl ester).

Structural Diagram is attached.

Explanation:

A.

Succinic anhydride appears as colorless needles or white crystalline solid. ... Succinic anhydride, also called dihydro-2, 5-furandione, is an organic compound with the molecular formula C4H4O3. It is the acid anhydride of succinic acid.

B.

Monomethyl succinate is a dicarboxylic acid monoester that is succinic acid in which one of the carboxy groups has been converted to its methyl ester. It is a dicarboxylic acid monoester and a hemisuccinate. ... They have the general structure RC(=O)OR', where R=fatty aliphatic tail or organyl group and R'=methyl group.

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation:

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