Answer:
The use of phenol (carbolic acid) as a wound disinfectant was first practiced by Lister. The correct option is E
Explanation:
Phenol( carbolic acid) is an aromatic organic compound. It has the following properties:
- it's soluble in water
- it's a weak acid and
- highly reactive toward electrophilic aromatic substitution
In Medical field, phenol was first used as an antiseptic by Joseph Lister.Joseph Lister was a student at University College London under Robert Liston, later rising to the rank of Surgeon at Glasgow Royal Infirmary. He believed that patients who passed through surgery, died due to infections caused by microorganisms.He theorized that if germs could be killed or prevented, no infection would occur. Lister reasoned that a chemical could be used to destroy the micro-organisms that cause infection. He made use of the carbolic acid by soaking a clean cloth in them, and placing it over the surgical wounds of patients.
Statement that when two elements combine with each other to from more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.
<u>Answer:</u> The atomic mass of these species is different and atomic number remains same.
<u>Explanation:</u>
Isotopes are the chemical species of the same element having different number of neutrons.
- Atomic number is equal to the number of protons or electrons present in that element.
Atomic Number = Number of electrons = Number of protons
- Atomic mass is defined as the sum of number of protons and neutrons contained in an atom.
Atomic Mass = Number of protons + Number of neutrons
For isotopes, as the number of neutrons differ, the atomic mass also differs.
For Example: Carbon has 3 naturally occurring isotopes:
. The atomic number remains the same but atomic mass differs.
Hence, for isotopes, the atomic mass of these species is different and atomic number remains same.
Answer:
Petrochemicals are chemical products derived from petroleum, although many of the same chemical compounds are also obtained from other fossil fuels such as coal and natural gas or from renewable sources such as corn, sugar cane, and other types of biomass.