For the α anomer of a d-sugar, the anomeric hydroxyl in a haworth projection a. has an upward projection (on the same side as the terminal ch₂oh group). b. has a downward projection (on the opposite side from the terminal ch₂oh group). c. may be either up or down, it depends on the individual sugar. d. is non-existent; anomers are a consideration only in fischer projections.

The correct option is: b. has a downward projection (on the opposite side from the terminal CH₂OH group).

Explanation:

The Haworth Projection depicts the three-dimensional cyclic structure of the monosaccharides.

The monosaccharide, D-glucose predominantly exists in the pyranose form and is known as D-glucopyranose. The D-glucopyranose has two anomeric forms: α- and the β- form and the carbon-1 (C-1 ) is known as the anomeric carbon.                

In the Haworth projection of α-D-glucopyranose, the hydroxyl group of anomeric carbon is projected in the downward direction. Whereas, the terminal CH₂OH group on the carbon-5 (C-5), is projected in the upward direction. Therefore, they are on the opposite sides of the plane of ring.

i believe it is c.) 1575 j.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"