Polysaccharides and disaccharides if they are neutral how do they undergo hydrolysis? When making a polysaccharide or a dissacharide dehydration synthesis occurs and why does it not get reversed immediately because of hydrolysis needing water. Do only soluble carbohydrates go through hydrolysis and the insoluble ones don't ?
Look at the picture below. You are right, if you add water to dissacharide, it will hydrolyze, that's why condensation builds up by removing solvent. If you remove water, equilibrium shifts to obtain more of it - thus, condensation proceeds. If you add water, equilibrium shifts to lose it - thus, hydrolysis proceeds (check for reversible reactions). All carbohydrates undergo hydrolysis, "insoluble" are those that bulk instead of dissolving when ingested (such as amylopectin or lignin). But they still can be digested - just find a right ferment for it, as microbes do!