$(NH_4)_2Cr_2O_7$ on heating gives:

Which of the following is not known?

The pair in which phosphorus atoms have a formal oxidation state of $+3$ is:

Ammonia is dried over

Given below are two statements:
Statement $I$: Like nitrogen that can form ammonia,arsenic can form arsine.
Statement $II$: Antimony cannot form antimony pentoxide.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which among the following is non-poisonous in nature?