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The observation that would provide the best evidence that a chemical reaction occurred is that The baking soda and hydrochloric acid combined, and bubbles formed.
When baking soda (NaHCO₃) and Hydrochloric Acid (HCl) combine, the following reaction happens:
NaHCO₃ + HCl → NaCl + H₂O + CO₂(g)↑
The gaseous Carbon Dioxide (CO₂) generated in this reaction is the responsible for the bubbles. The releasing of this gas is an evidence that a chemical reaction occurred between NaHCO₃ and HCl.
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In this redox reaction, the Cu goes from oxidation state of (0) to (+2), therefore it oxidises. N in HNO₃ goes from oxidation state of (+5) to N in NO with oxidation state of (+2) and becomes reduced.
Cu acts as the reducing reagent and HNO₃ is the oxidising agent.
oxidation half reaction
Cu ---> Cu²⁺ + 2e --1)
reduction half reaction
4H⁺ + 3e + NO₃⁻ ---> NO + 2H₂O --2)
to balance the number of electrons , 1) x3 and 2) x2
3Cu ---> 3Cu²⁺ + 6e
8H⁺ + 6e + 2NO₃⁻ ---> 2NO + 4H₂O
add the 2 equations
3Cu + 8H⁺ + 2NO₃⁻ ---> 3Cu²⁺ + 2NO + 4H₂O
add 6 nitrate ions to both sides to add up to 8 and form acid with 8H⁺ ions
3Cu + 8HNO₃ ---> 3Cu(NO₃)₂ + 2NO + 4H₂O
Balanced equation for the redox reaction is as follows;
3Cu(s) + 8HNO₃(aq) → 3Cu(NO₃)₂(aq) + 2NO(g) + 4H₂O<span>(l)
NO has a coefficient of 2
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C.
Water is polar because one side of the molecule is positive and the other is negative.
The hydrogen deficiency index( HDI) of strigol is = 10
<h3>How to calculate HDI:</h3>
The hydrogen deficiency index is used to measure the number of degree of unsaturation of an organic compound.
Strigol is an example of an organic compound because it contains carbons and hydrogen.
To calculate the HDI using the molecular formula given (C19H20O6) the formula for HDI is used which is:
where C = number of carbon atoms = 19
n= number of nitrogen atoms = 0
h= number of hydrogen atoms = 20
X = number of halogen atoms = 0
Note that oxygen was not considered because it forms two bonds and has no impact.
There for HDI =
HDI=
HDI =
HDI = 10
Therefore, the hydrogen deficiency index of strigol is = 10
Learn more about unsaturated compounds here:
brainly.com/question/490531
