Why does your dog have white stools?
Speaking to my local vet, white stools from dogs (rarely seen these days) were due to eating bones. Remember when we used to go to local butchers instead of supermarkets and they used to give them out for free? As bones cannot be digested and together with high amounts of calcium and marrow, dog stools turned white! If this same problem is happening to anyone you know, I'd get them to seriously look into their diet - or visit the doctor ASAP.
It could be anything from too many fats in the dog's diet, to have a bit of an intestinal problem (we all get them). Even humans can have a certain amount of mucus in their stools. If your dog's stools are quite white with mucus then it's advisable to take a stool sample to your vets for analysis to be sure there is no infection.
Of coarse you can feed your dog white rice, because can you feed your dog white rice? is saying do you have the ability to feed your dog white rice. Of coarse you have the ability to feed your dog white rice, but if you will feed your dog white rice is your choice. you should have asked, is it healthy for your dog to eat white rice? instead.