A metal was burnt in air. The substance formed was dissolved in water and tested with blue and red litmus paper. What result can we expect ?

As metal on burning form metal oxide, which are basic in nature therefore we can expect that red litmus will turn blue and there would be no effect on blue litmus paper. 
For reason you may refer to the following link:
https://www.meritnation.com/ask-answer/question/i-did-not-understand-why-metal-oxides-are-called-basic-oxid/acids-bases-and-salts/1111338