It was discovered in 1868.i hope this helps you .
Answer:
Both sodium and calcium.
Explanation:
The membrane potential is maintained inside and outside of the cell due to the unequal distribution of the different ions. This membrane potential difference is important for the generation of action potential.
The resting membrane potential is around +30 mV. This is due to the presence of potassium ions. The sodium and calcium ions must enter in the cell to change this membrane potential and generates the action potential in the body.
Thus, the correct answer is option (3).
Answer:
With Br2 - Bromobenzene
With Cl2 - Chlorobenzene
With HNO3- Nitrobenzene
With H2SO4 - Benzenesulphonic acid
With HCOCl - Benzoyl chloride
With 1-chloro-2,2-dimethylpropane - 2,2dimethyl-1-phenyl propane
Explanation:
The common thread joining all these reactions is that they are all electrophillic reactions. They are so called because the attacking agents in each reagent is an electrophile. Electrophiles are species that have electron deficient centers and are known to attack molecules that are high in electron density at regions of high electron density.
The benzene molecule has rich electron density. Any substituents that donates electrons to the ring improves the likelihood that benzene will undergo electrophillic substitution reactions while electron withdrawing substituents decrease the likelihood that benzene will undergo electrophillic substitution reactions.
The names of the compounds formed when benzene undergoes electrophillic reaction with the attacking agents listed in the question are displayed in the answer section.
1) Write the balanced chemical equation
2HCl + Na2 CO3 ----------> 2NaCl + H2CO3
2) Write the molar ratios:
2 mol HCl : 1 mol Na2CO3 : 2 mol NaCl : 1 mol H2CO3
3) Convert 0.15g of sodium carbonate to number of moles
3a) Calculate the molar mass of Na2CO3
Na: 2 * 23 g/mol = 46 g/mol
C: 12 g/mol =
O: 3 * 16 g/mol = 48 g/mol
molar mass = 46g/mol + 12g/mol + 48g/mol = 106 g/mol
3b.- Calculate the number of moles of Na2CO3
# moles = grams / molar mass = 0.15 g / 106 g/mol = 0.0014 mol Na2CO3
4) Calculate the number of moles of HCl from the molar proportion:
[0.0014 mol Na2CO3] * [2 mol HCl / 1 mol Na2CO3] = 0.0028 mol HCl
5) Calculate the volume of HCl from the definition of Molarity
Molarity, M = # moles / volume in liters
=> Volume in liters = # moles / M = 0.0028 mol / 0.1 M = 0.028 liters
0.028 liters * 1000 ml / liter = 28 ml.
Answer: 28 mililiters of 0.1 M HCl.
Out of the options, the best indicator is a color change since it is the only one that can't really be blamed on a physical change. you will eventually notice that during qualitative labs and some quantitative labs, usually the thing that you are looking for is either color change or the production of a precipitate to indicate the presence of a chemical reaction
