If the adhesive is not cement based you could try sprinkling water to the wall to ease the scrapping process.
Remove plastic tile glue from wall.
The heat will soften the adhesive.
How to remove ceramic tile glue from a wall.
If you want to get rid of it you might be considering removing the tile.
The adhesive that was used in a lot of these installations is very tough and you might even find that it is still not completely cured behind the tile.
Press the tip of the scraper at a joint in the tiles.
Scrape the surface of the adhesive with a stiff bristle brush.
Look for a formula that is either made for ceramic tile.
Lower the handle of the scraper to a 45 degree angle and push down to drive the scraper s.
Irrespective of the adhesive formula you have to cover the floor with old cloths as to protect it from the residues which will fall off the wall.
Since not all will come off there will be an uneven layer of adhesive left behind.
Usually when you chisel the tiles off most of the thin set mortar will be removed with it.
Step 3 wipe some tile adhesive remover over the surface of the wall.
How to remove plastic tile glue grout.
Wait several minutes and use a large scrapper to remove the mastic.
It scraped off pretty easy after it softened up in 10 15 minutes.
A good option to address the old plastic wall tile is to cover it with decorative panels.
You will then have to pry off the leftover residue.
Mine are plaster and the best thing that worked was to soak the glue on the wall with hot soapy water.
If any adhesive gets stuck to the brush remove it by hand and continue until no more adhesive remains on the wall.
Aim the heat gun at the remaining adhesive that was below the tiles.
Just answered your thread about repairing walls after removing wallpaper but i would recommend a completely different approach for the walls in this photo.
Apply some water to a small section of the adhesive.
If the adhesive used was organic mastic the water will begin to soften it allowing you to.
Apply an adhesive removing paste to the wall.