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GATE 2022 CY – Question 17

Inorganic Chemistry · Instrumental Methods of Analysis: UV-visible, fluorescence and FT-IR spectrophotometry, NMR and ESR spectroscopy, mass spectrometry, atomic absorption spectroscopy, Mössbauer spectroscopy (Fe and Sn) and X- ray crystallography. Electroanalytical methods – cyclic voltammetry, ion-selective electrodes. Thermo-analytical methods: TGA, DTA and DSC. · 1 mark · Multiple choice

In differential thermal analysis (DTA)

  1. the temperature differences between the sample and reference are measured as a function of temperature
  2. the differences in heat flow into the reference and sample are measured as a function of temperature
  3. the change in the mass of the sample is measured as a function of temperature
  4. the glass transition is observed as a sharp peak

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Correct answer: (A) the temperature differences between the sample and reference are measured as a function of temperature

Explanation

DTA monitors the temperature difference between a sample and an inert reference while both follow the same heating programme.

Thus **A** is correct. Differential scanning calorimetry instead measures heat-flow difference, and thermogravimetry measures mass change; glass transitions typically give baseline changes rather than sharp melting-like peaks.