You needed to make sure your glassware was dry before proceeding with the hydroboration reaction and an excess of hydroborane was used to counter the small amounts of water present in the reaction. Why is the borane-THF reagent so reactive with water? Hint: What is the electronegativity of B compared to H?

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.