Fuel cells can make an electricity from a simple electrochemical
reaction in which oxygen and hydrogen combine to form water. There are several
different types of fuel cell but they are all based around a central design
which consists of two electrodes, a negative anode and a positive cathode.
These are separated by a solid or liquid electrolyte that carries electrically
charged particles between the two electrodes. A catalyst, such as platinum, is
often used to speed up the reactions at the electrodes. Fuel cells are
classified according to the nature of the electrolyte. Every type needs
particular materials and fuels and is suitable for any applications. The
article below uses the proton exchange membrane fuel cell to illustrate the
science and technology behind the fuel cell concept but the characteristics and
applications of the other main designs are also discussed. Proton Exchange Membrane Fuel Cells (PEMFC)
The hydrogen ions permeate across the electrolyte to the
cathode, while the electrons flow through an external circuit and provide
power. Oxygen, in the form of air, is supplied to the cathode and this combines
with the electrons and the hydrogen ions to produce water. These reactions at
the electrodes are as follows:
Anode: 2H24H+ + 4e-
Cathode: O2 + 4H+ + 4e- 2H2O
Overall: 2H2 + O22H2O + energy
PEM cells operate at a temperature of around 80°C. At this
low temperature the electrochemical reactions would normally occur very slowly
so they are catalysed by a thin layer of platinum on each electrode.
Explanation:
The act of aspiring or ardently desiring; an ardent wish or desire, chiefly after what is elevated or spiritual (with common adjunct adpositions being to or of)
Answer:
Option D and E
Explanation:
Hope it was helpful for u
Answer:
Plant biotechnology can be defined as the use of tissue culture and genetic engineering techniques to produce genetically modified plants that exhibit new or improved desirable characteristics.
Explanation:
These crops offer several benefits both farmers and consumers.
...
Pocket K No. 2: Plant Products of Biotechnology.
Product Trait
Bean Virus disease resistance
Canola Herbicide tolerance, modified oil/fatty acid, pollination control system, phytase production
Cotton Herbicide tolerance, insect resistance, low gossypol
Eggplant Insect resistance
Answer: Option C.
Inefficient oxygen transportation.
Explanation:
Sickle cell anaemia is an inheritable condition in which the red blood cells cannot carry oxygen to the organs or whole body because the red blood cells shape has been distorted and is sickle in shape. In this condition there is not enough red blood cells to carry oxygen in the blood.
Red blood cells function to transport oxygen in the blood because of the haemoglobin molecule present in them.
This can damage the organs nerves,lungs, livers spleen e.t.c
