 # Add the solutions of the following four substances a into four beakers containing 10ml 2mol / L hydrochloric acid respectively, and dilute them to 50ml with water. At this time, a and hydrochloric acid react slowly, and the maximum chemical reaction rate in the middle of the period is () A.10mL 1mol/L B.20mL 1mol/L C.10mL 2mol/L D.20mL 2mol/L

## Add the solutions of the following four substances a into four beakers containing 10ml 2mol / L hydrochloric acid respectively, and dilute them to 50ml with water. At this time, a and hydrochloric acid react slowly, and the maximum chemical reaction rate in the middle of the period is () A.10mL 1mol/L B.20mL 1mol/L C.10mL 2mol/L D.20mL 2mol/L

If D is selected, the reaction with the largest concentration is fast

### Add the following four kinds of sodium bicarbonate solutions into four containers containing 10ml   Dilute 2mol • L-1 hydrochloric acid beaker with water to 50ml. At this time, sodium bicarbonate reacts with hydrochloric acid, and the highest rate per hour at the beginning of the reaction is () A. 20ml 3mol • L-1 sodium bicarbonate solution at 10 ℃ B. 30ml 2mol • L-1 sodium bicarbonate solution at 20 ℃ C. 10ml 4mol • L-1 sodium bicarbonate solution at 20 ℃ D. 20ml 2mol • L-1 sodium bicarbonate solution at 10 ℃

A. 20ml3 mol • L-1 sodium bicarbonate solution, when diluted to 50ml, the concentration is 1.2mol • L-1;
B. 20ml 3mol • L-1 sodium bicarbonate solution, when diluted to 50ml, the concentration is 1.2mol • L-1;
C. 10ml of 4mol • L-1 sodium bicarbonate solution, when diluted to 50ml, the concentration is 0.8mol • L-1;
D. 20ml of 2mol • L-1 sodium bicarbonate solution, when diluted to 50ml, the concentration is 0.8mol • L-1,
Obviously, 10ml in four cases   When 2mol • L-1 hydrochloric acid is diluted to 50ml with water, the concentration is. 4mol • L-1,
Because the temperature and concentration in B are the highest, the reaction rate is the highest,
Therefore: B

### Add the following four different volumes and concentrations of ABCD Na2S2O3 solutions into four beakers containing 10ml 2mol / L hydrochloric acid solution And quickly add water to dilute to 50ml. At this time, the maximum chemical reaction rate between Na2S2O3 and hydrochloric acid solution is: A:10ml 4mol/L B; 20 3 20 2 10 2

Indeed, the higher the ion concentration here, the faster the reaction
Since it is quickly diluted to 50ml with water, it must be compared according to the amount of ionic substances before dilution
A 10*4=40mmol
B 20*3=60mmol
C 20*2=40mmol
D 10*2=20mmol
Therefore, the concentration of B after dilution is the largest, and the answer is B

### Add the following four kinds of X solutions into four containers respectively and hold 10ml   In a beaker of 2mol / L hydrochloric acid, add water to dilute to 50ml at the same time. At this time, X reacts slowly with hydrochloric acid. Among them, the highest reaction rate is () A. 20ml 3mol / L x solution at 10 ℃ B. 30ml 2mol / L x solution at 20 ℃ C. 10ml 4mol / L x solution at 20 ℃ D. 10ml 2mol / L x solution at 10 ℃

A. 10 ℃ 20ml3mol / L x solution, the amount of substance x is 0.02l × 3mol/L=0.06mol；
B. 30ml 2mol / L x solution at 20 ℃, and the amount of substance x is 0.03l × 2mol/L=0.06mol；
C. 10ml 4mol / L x solution at 20 ℃, and the amount of substance x is 0.01L × 4mol/L=0.04mol；
D. 10 ℃ 10ml 2mol / L x solution, the amount of substance x is 0.01L × 2mol/L=0.02mol，
Obviously, in the four cases B, the temperature is the highest and the concentration is the largest, so the reaction rate is the largest,
Therefore, B

### The chemical reaction with oxygen must be oxidation, right

No. the reaction of 3O2 = 2O3 involves oxygen, but it is not a redox reaction, because it does not involve electron transfer

### Is oxygen an oxidant or an oxidation reaction

It depends on the reaction of oxygen