Which element is reduced in this reaction? 16h++2cr2o72−+c2h5oh→4cr3++11h2o+2c o2?

Cr atoms undergo a reduction reaction (decrease in oxidation number) from +6 to +3

Reduction oxidation reaction or abbreviated Redox is a chemical reaction in which there are changes in oxidation numbers

The general formula for determining oxidation numbers:

On reaction :

16H⁺ + 2Cr₂O₇²⁻ + C₂H₅OH → 4Cr³⁺+ 11H₂O + 2CO₂

Oxidation number at C₂H₅OH

2. C + 6. H + O = 0

2C + 6. + 1 + (-2) = 0

2C + 6 -2 = 0

2C + 4 = 0

2C = -4

C = -2

Oxidation number at CO₂

C + 2.O = 0

C + 2.-2 = 0

C = 4

The oxidation number C in C₂H₅OH is -2 and the oxidation number C in CO₂ is +4, the change in oxidation number C from -2 to +4 is 6, so the C atom experiences an oxidation reaction (increase in oxidation number)

Oxidation number at Cr₂O₇²⁻

2. Cr + 7. O = -2

2. Cr + 7.-2 = -2

2Cr -14 = -2

2Cr = 12

Cr = 6

Cr³⁺ = 3

The oxidation number Cr in Cr₂O₇²⁻ is +6 and the oxidation number Cr in Cr³⁺ is +3, the change in Cr oxidation number from +6 to +3 is -3, so that the Cr atom experiences a reduction reaction (decreasing the oxidation number)

While O and H atoms do not experience changes in oxidation numbers (O = -2 and H = +1)

an oxidation-reduction reaction

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a reducing agent during a redox reaction

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loses electrons in a chemical reaction

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Keywords: reduction, oxidation

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.