Chemistry, 08.07.2020 14:01 jordanfwtm

4. In which pair of substances does the first underlined atom have a lower oxidation number than the second? A. NH3OH+ NH4– B. H2O H2O2 C. SO3 SO42– D. HCHO C

Answers: 3

Show answers

Answers

Answer from: ReaFam

Option B is correct.

Only this option has the first underlined element with a lower oxidation number than the second amongst the options.

Explanation:

Complete Question

In which pair of substances does the first underlined atom have a lower oxidation number than the second?

A. NH₃OH⁺, NH₄⁻ (N is underlined)

B. H₂O, H₂O₂ (O is underlined)

C. SO₃, SO₄²⁻ (S is underlined)

D. HCHO, C (C is underlined)

Solution

In determination of the oxidation number of an atom in a compound, we first name the unknown oxidation number x.

Then, the total oxidation number of the atoms in the compound is equal to the charge of on the compound (or radical).

So, elements in their neutral state have no charge and no oxidation number.

A. NH₃OH⁺, NH₄⁻ (N is underlined)

N in NH₃OH⁺

Oxidation number of N = x

Oxidation number of H = +1

Oxidation number of O = -2

x + (3×+1) + (-2) + (+1) = +1

x - 3 - 2 + 1 = 1

x = +5

N in NH₄⁻

Oxidation number of N = x

Oxidation number of H = +1

x + (4×1) = -1

x + 4 = -1

x = -1 - 4 = -5

First underlined element has a greater oxidation number than the second. So, this doesn't qualify.

B. H₂O, H₂O₂ (O is underlined)

O in H₂O

Oxidation number of H = +1

Oxidation number of O = x

(2×1) + x = 0

2 + x = 0

x = -2

H₂O₂

Oxidation number of H = +1

Oxidation number of O = x

(2×1) + (2×x) = 0

2 + 2x = 0

2x = -2

x = (-2/2) = -1.

First underlined element has a lower oxidation number than the second. So, this qualifies.

C. SO₃, SO₄²⁻ (S is underlined)

S in SO₃

Oxidation number of S = x

Oxidation number of O = -2

x + (3×-2) = 0

x - 6 = 0

x = +6

SO₄²⁻

Oxidation number of S = x

Oxidation number of O = -2

x + (4×-2) = -2

x - 8 = -2

x = 8 - 2 = +6

First underlined element has the same oxidation number as the second. So, this doesn't qualify.

D. HCHO, C (C is underlined)

C in HCHO

Oxidation number of H = +1

Oxidation number of C = x

Oxidation number of O = -2

+1 + x + 1 - 2 = 0

x = 0

C in C

Oxidation number of C = x

x = 0

First underlined element has the same oxidation number as the second. So, this doesn't qualify.

Hope this Helps!!!

Answer from: Quest

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

Answer from: Quest

Yes i think so not 100 percent sure though

Another question on Chemistry

Chemistry, 22.06.2019 05:50

What are transitions between a liquid and gas called? identify which way they are transitioning

Answers: 2

Answer

Chemistry, 22.06.2019 06:00

24. a sports ball is inflated to an internal pressure of 1.85 atm at room temperature (25 °c). if the ball is then played with outside where the temperature is 7.5 °c, what will be the new pressure of the ball? assume the ball does not change in volume nor does any air leak from the ball a) 0.555 atm b) 1.74 atm c) 1.85 atm d) 1.97 atm

Answers: 2

Answer

Chemistry, 22.06.2019 14:50

How are evaporation and sublimation similar? a both involve the formation of a gas. b both release energy to the surroundings. c both take place throughout a solid. d both take place at the surface of a liquid.

Answers: 1

Answer

Chemistry, 22.06.2019 18:00

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?

Answers: 2

Answer

You know the right answer?

4. In which pair of substances does the first underlined atom have a lower oxidation number than the...

Questions