Question

120 100 80 60 운 40 20 700 600 500 0 400 300 200 100 0 Time (seconds) Inside1 Outside1 Inside2 Outside2

(inside: polyaniline sensor inside a jar which is in contact with vinegar vapors... outside: polyaniline sensor when it is outside of the jar)

Q1)Analysing the results from the graph of resistance vs time when the sensor was exposed to vinegar, does the polyaniline sensor adequately perform its function as a sensor? If so, then list a potential application of such a sensor.

Q2)How might you improve the sensor? For this question think first about what a good sensor should be then address how the sensor made here could be made better in that context. Do not simply say that being more careful or getting a more experienced scientist to do the experiment is the way to improve it.

Answer 1

1. vinegar is a liquid having 5-20% acetic acid. This acid is responsible for resistance change in the sensor,

Reduction reaction when occurs between electrodes we can monitor using this sensor. as resistance is inversely proportional to conductivity. from graph we can see resistance decrease with time. that is solution becomes more conducting with time. this sensor can be used to monitor the reaction rate.

2. effect of particle size decrease leads to improve sensitivity and speed of response of sensor.