how do i unclog kitchen plumbing in a double wide manufactured home?

the "snake" goes about 12 feet and stops. the p trap is clear. i opened the plug where the pipe goes under the floor and put in the snake. i atttached a hose to the faucet and put water down to clear out debris dislodged by snake. i then put the sulfuric acid drin opener in but it has not disolved the clog. i repeated the flushing. it must be at and elbow to the rest of the house plumbing. i tried getting to it thru the washer drain but no l uck.