For no2−, write an equation that shows how the anion acts as a base. express your answer as a chemical equation. identify all of the phases i

The chemical reaction in which NO2^- acts as a base is;  H3O^+(l) + NO2^- (aq) > HNO2(aq) + H2O(l)

According to the Brownstead - Lowry definition of acids and bases, an acid is any substance that donates a proton while a base is any substance that accepts a proton. Hence, the NO2^- ion acts as a base in reactions where it accepts a proton to yield its conjugate acid.

In the reaction; H3O^+(l) + NO2^- (aq) > HNO2(aq) + H2O(l), we can see that the NO2^- accepted a proton from H3O^+ to yield its conjugate acid  HNO2.

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a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.