Acid And Base Exercise

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Ten men and one woman were studied before, during, and following five 1-min cycling bouts (100% VO2 max) 1 h after consuming either 0.2 g/kg B.W. of NaHCO3 or a placebo drink (NaCl). The fifth exercise bout was performed until exhaustion and the time recorded to judge the effects of the NaHCO3 drink on performance. Blood samples taken from a forearm vein revealed that the intake of NaHCO3 increased resting pH (7.34 to 7.41), HCO3 (27.5 to 31.0 mM), and base excess (1.1 to 4.6 mM). During and following the exercise, blood pH and HCO3 were always higher (P less than 0.05) in the NaHCO3 than placebo trial. Performance times during the fifth cycling bout averaged 113.5 (SE +/- 12.4) and 160.8 (SE +/- 19.1) s in the NaCl and NaHCO3 trials, respectively. This 42% difference between the means was significant at the 0.01 level. The blood hydrogen ion to lactic acid ratios (nM/mM) measured between each exercise bout and during recovery from the exhaustive fifth bout suggests that the enhanced performance during the NaHCO3 trial was the result of greater buffer capacity. Thigh muscle (vastus lateralis) pH measured immediately before the fifth cycling bout in four of the subjects revealed that the working muscles were less acid in the NaHCO3 trial (pH = 6.81) than during the NaCl treatment (pH = 6.73). Thus, the alkalizing influence of oral HCO3 supports the concept that the hydrogen ion concentration in blood and muscle has a direct influence on performance during repeated, supramaximal exercise.

Transitions between rest and work, in either direction, and heavy exercise loads are characterized by changes of muscle pH depending on the buffer power and capacity of the tissues and on the metabolic processes involved. Among the latter, in chronological sequence: (1). aerobic glycolysis generates sizeable amounts of lactate and H(+) by way of the recently described, extremely fast (20-100 ms) "glycogen shunt" and of the excess of glycolytic pyruvate supply; (2). hydrolysis of phosphocreatine, tightly coupled with that of ATP in the Lohmann reaction, is known to consume protons, a process undergoing reversal during recovery; (3). anaerobic glycolysis sustaining ATP production in supramaximal exercise as well as in conditions of hypoxia and ischemia, is responsible for the accumulation of large amounts of lactic acid (up to 1 mol for the whole body). The handling of metabolic acids, i.e., acid-base regulation, occurs both in blood and in tissues, mainly in muscles which are the main producers and consumers of lactic acid. The role of both blood and muscle bicarbonate and non-bicarbonate buffers as well as that of lactate/H(+) cotransport mechanisms is analyzed in relation to acid-base homeostasis in the course of exercise. A section of the review deals with the analysis of the acid-base state of humans exposed to chronic hypoxia. Particular emphasis is put on anaerobic glycolysis. In this context, the so-called lactate paradox is revisited and interpreted on the basis of the most recent findings on exercise at altitude.

NCERT Solutions for Class 10 Science Chapter 2 Acids, Bases and Salts are prepared to help students in their CBSE exam preparation. This solution provides them with answers to the questions provided in the NCERT Class 10 textbooks. To score better marks in Class 10 Science examination, students should get well-versed with the NCERT Solutions for Class 10 Science provided here.

Every year, 3-4 questions from this chapter are asked in the Class 10 examination. This is also one of the important chapters, as the chances of scoring full marks on questions from this chapter are more. Hence, students are advised to practise all questions of this chapter using these NCERT Solutions for Class 10 Science. Access the NCERT Solutions of Class 10 Science of this chapter from the link given below.

1. You are given three test tubes. The three test tubes contain distilled water, an acidic solution and the basic solution, respectively. There is only red litmus paper available in order to identify what is there in each test tube. How will you find out what is in each of the test tubes?

NOTE: After immediate distillation, distilled water has a pH of 7. However, within a few hours after distillation, it absorbs carbon dioxide from the atmosphere and turns slightly acidic with a pH of 5.8.

3. Metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.

Solution: As the metal compound released is Calcium Chloride, the gas evolved here is CO2. Hence, metal A should be Calcium Carbonate. Hence, the reaction between Calcium Carbonate and HCl is

Solution: Release of H+ ion in water will make a compound acidic or non-acidic. Acids are substances which, upon dissociating with water, resulting in the production of Hydrogen ions. Some compounds show an acidic character as they dissociate in the aqueous solution, which results in the production of hydrogen ions (acids like HCl, HNO3).

Compounds similar to glucose or alcohol do contain a hydrogen element, but they do not show signs of acidic nature. The fact is that the hydrogen in them will not separate from like the hydrogen in the acids. They will not separate to become hydrogen ions, on dissolving in the water.

Solution: Charged particles are responsible for the conductance of electricity in an acid. These charged particles, called ions, are the reason behind the conductance of electricity in acid.

Solution: While diluting an acid, it is recommended that the acid should be added to water and not water to the acid because if water is added to a concentrated acid, it releases a huge amount of heat which may result in an explosion and can cause acid burns on the face, clothes and body parts. Hence, it is safe to add acid to water but not water to acid.

Solution: When acid is added to water, there will be a fixed amount of hydronium present in the fixed volume of the solution. If we dilute the solution, hydronium ions per volume of the solution decrease, and this, in turn, decreases Hydronium concentration in the solution.

Solution: When a base is dissolved in sodium hydroxide solution, its hydroxide ions increase, but it will reach saturation at some point. After saturation point, hydroxide ion concentration is not affected even after adding base further.

1. You have two solutions, A and B. The pH of solution A is 6, and the pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of these is acidic, and which one is basic?

Solution: Hydrogen ion concentration decides the nature of the solution. If Hydrogen ion concentration increase, then the solution turns acidic and similarly, if Hydrogen ion concentration decreases, then the solution turns basic.

4. Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide), or chalk (calcium carbonate)?

3. 10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be

Solution: Insert two nails into the wooden or rubber cork and place them on a beaker, as shown in the figure. Connect the iron nail to a bulb, a 6-volt battery and a wire connected to the switch. Pour some alcohol or glucose so as to dip the nails in glucose or alcohol. Turn the switch on, and you see the bulb not glowing despite of connection to the switch. Now empty the beaker and add the HCL solution. This time, the bulb glows. This proves acid can conduct electricity, but alcohol and glucose do not conduct electricity.

Solution: The acidic behaviour of acids is because of the presence of hydrogen ions. Hydrogen ions can only be produced in the presence of water, and therefore, water is definitely needed if acids are to show their acidic behaviour.

10. Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. Amount and concentration taken for both the acids are the same. In which test tube will the fizzing occur more vigorously and why?

Solution: HCl is a strong acid, whereas acetic is a weaker acid. Fizzing occurs because of the production of the hydrogen gas obtained due to the reaction of the acid on the magnesium ribbon. Since HCl is a very strong acid, there is a lot of liberation of hydrogen gas from test tube A. Therefore, more fizzing takes place in test tube A.

Solution: Plaster of Paris should be stored in a moisture-proof container because moisture can affect the Plaster of Paris by slowing down the setting of the plaster because of hydration. This will turn plaster useless.

In this chapter, students will get a hold of basic knowledge of acids, bases and salts. Students can further learn by accessing the Class 10 NCERT Solutions, the various chemical properties of acids, bases and salts and their reaction with metals and non-metals.

* You can use a straw as a dropper. First, dip the straw into the liquid. Place a finger over the top of the straw to make a seal. When you remove the straw from the liquid, the liquid will remain inside the straw. When you are ready to release the liquid, remove your finger from the top of the straw.

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