List of top Air and Noise Pollution Questions on Gas laws asked in GATE ES

A sample of air is collected in the morning at an ambient temperature of 25°C. The concentration of carbon monoxide (CO) in this sample is 30 ppmv (ppm by volume). The same sample is analysed later in the afternoon when the sample temperature is 35°C. The analysis results will show the CO concentration as _______.
The concentration of NO\(_2\) in the air at NTP is reported as 0.30 ppm (ppm by volume). The concentration of NO\(_2\) in \(\mu g/m^3\) is _______ (rounded off to the nearest integer).
In proximate analysis, when a 10 kg moisture-free solid sample is heated in a furnace at 950 °C in the absence of air, its mass is reduced by 6 kg. If the same 10 kg moisture-free solid sample is heated in the furnace at the same temperature in the presence of air, its mass is reduced by 7 kg. The percentage of fixed carbon in the sample is _______.