Which of the following is a reason why tetramethylsilane (TMS), Si(CH3)4\text{Si(CH}_3)_4Si(CH3)4, is used as a standard for NMR chemical shift measurements?
It contains 12 equivalent protons, producing a single, intense peak at δ=0 ppm\delta = 0\text{ ppm}δ=0 ppm.
It is a highly polar compound, making it an excellent solvent for ionic analytes.
Its protons are highly deshielded, so its peak is located downfield of most organic signals.
It is highly reactive, allowing it to easily derivatize the sample molecules.
28 exam-style questions on OCR A A Level Chemistry Spectroscopy. Each one has a worked solution and a mark scheme showing where the marks go.