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Chemical formula

Example: Balanced Chemical Equations with Subscripts Water: $$\ce{H2O}$$ Carbon dioxide: $$\ce{CO2}$$ Iron(III) hydroxide (Rust reaction): $$\ce{4Fe + 3O2 + 6H2O -> 4Fe(OH)3}$$ Copper(II) sulfate pentahydrate: $$\ce{CuSO4 * 5H2O}$$ Chemical Formulas in Chemistry Chemical formulas are the symbolic representations of chemical substances. They show the elements present in a compound and the ratio in which the atoms of these elements combine. Chemical formulas are essential for understanding the composition, structure, and behavior of compounds in chemical reactions. 1. What is a Chemical Formula? A chemical formula uses symbols of elements and numerical subscripts to represent the composition of a substance. For example, the formula for water is: $$ \ce{H2O} $$ This indicates that each water molecule is made up of 2 atoms of hydrogen and 1 atom of oxygen. 2. Types of Chemical Formulas Empirical Formula Molecular Formula Structural Formula...

IIT Practice_1

         IIT Jee Preparation 
                       


1. If C is a skew - symmetric matrix of order n and X is n x 1 column matrix , then X'CX is a : 

 (a) scalar matrix 
 (b) unit matrix 
 (c) null matrix 
 (d) none of these 

Answer : (c) 

2. If A^2 = A , then (I + A)^4 is equal to : 

 (a) I + A 
 (b) I + 4A 
 (c) I + 14A 
 (d) I + 15A 

Answer : (d) 

3. In a triangle ABC , if sinA sinB sinC = p , cos A cosB cosC = q , then tanA , tanB , tanC are the roots of the equation : 

(a) qx^3 + px^2 - ( 1 + q ) x + p = 0 
(b) qx^3 - px^2 + ( 1 + q )x - p = 0 
(c) qx^3 - ( 1 + p ) x^2 + qx - p = 0 
(d) qx^3 - ( 1 + p ) x^2 + ( 1 + q )x - p = 0 

Answer : (b) 

4. In a triangle ABC , r^2 + r1^2 + r2^2 + r3^2 + a^2 + b^2 + c^2 is equal to : 

(a) 4R^2 
(b) 8R^2 
(c) 12R^2 
(d) 16R^2 

Answer : (d) 

5.    A + 4HIO4    ---->  3HCOOH + HCHO + CHO -         COOH  
 Glucose derivative 'A' is / are : 

(a) gluconic acid 
(b) glucaric acid 
(c) glucitol 
(d) glucouronic acid 

Answer : (a) 

6. Which of the following is true about the complex [ ptCl2(NH3)(OH2)] ? 

(a) It exhibits geometrical isomerism 
(b) It is paramagnetic complex 
(c) It's geometry is not square planer 
(d) Platinum is sp3 hybridized 

Answer : (a) 

7. An ideal gas expands in such a manner that it pressure and volume can be related by equation PV^2 = constant . During this process , the gas is 

(a) heated 
(b) cooled 
(c) neither heated not cooled 
(d) first heated and then cooled 

Answer : (b) 

8. If pressure of a gas contained in a closed vessel is increased by 0.4% when heated by 1°C , the initial temperature must be 

(a) 250 K 
(b) 250° 
(c) 2500 K 
(d) 25°C 

Answer : (a) 

9. Ethylene glycol is used as an antifreeze in a cold climate . Mass of ethylene glycol which should be added to 4 kg of water to prevent it from freezing at - 6°C will be : 

(a) 204.30 g 
(b) 400.00 g 
(c) 304.60 g 
(d) 804.32 g 

Answer : (d) 

10. If an aqueous solution of glucose is allowed to freeze , then crystals of which will be separated out first ? 

(a) glucose 
(b) water 
(c) both of these 
(d) none of these 

Answer : (b) 

11. A beaker is completely filled with water at 4°C . It will overflow if 

(a) Heated above 4°C 
(b) Cooled below 4°C 
(c) Both heated and cooled above and below 4°C  respectively 
(d) None of these 

Answer : (c) 

12. A solid cube and a solid sphere of the same material have equal surface area . Both are at the same temperature 120°C . Then 

(a) both the cube and the sphere cool down at the same rate 
(b) The cube cools down faster than the sphere 
(c) The sphere cools down faster than the cube 
(d) Whichever is having more mass will cool down faster 

Answer : (b) 

13. A particle executing SHM of amplitude 'a' has a displacement a/2 at t = T/4 and a negative velocity . The epoch of the particle is 

(a) π/3 
(b) 2π/3 
(c) π
(d) 5π/3 

Answer : (a) 

14. The area of the region bounded by the parabola y = x^2 + 1 and the straight line x + y = 3 is given by 

 (a) 45/7 
 (b) 25/4 
 (c) π/18
 (d) 9/2 

Answer : (d) 

15. An increase in intensity level of 1dB implies an increase in density of 

(a) 1% 
(b) 3.01% 
(c) 26% 
(d) 0.1%

Answer : (c) 

16. The molarity of 900 g of water 💦 is 

 (a) 50 M 
 (b) 55.5 M 
 (c) 5 M 
 (d) cannot be calculated 

Answer : (b) 

17. In comparision to a 0.01 M solution of glucose , the depression in freezing point of a 0.01 M MgCl2 solution is ....

(a) the same 
(b) about twice 
(c) about three times 
(d) about six times 

Answer : (c) 

18. The displacement of a particle is given by x = 3 sin (5πt) + 4 cos(5πt) . The amplitude of particle is 

 (a) 3
 (b) 4
 (c) 5
 (d) 7 

Answer : (c) 

19. The equation of the common tangent to the curves y^2 = 8x and xy = -1 is 

(a) 3y = 9x + 2 
(b) y = 2x + 1
(c) 2y = x + 8 
(d) y = x + 2 

Answer : (d) 

20. Four moles of hydrogen , 2 moles of helium and 1 mole of water vapour form an ideal gas mixture . What is the molar specific heat at constant pressure of mixture ? 

(a) 16/7 R
(b) 7 R / 16
(c) R
(d) 23/7 R

Answer :(d)

21. The amount of solute ( molar mass 60 g/mol ) that must be added to 180 g of water so that the vapour pressure of water is lowered by 10% is 

(a) 30 g
(b) 60 g 
(c) 120 g 
(d) 12 g 

Answer : (b) 

22. A simple pendulum oscillates slightly above a large horizontal metal plate . The bob is given a charge . The time period 

(a) has no effect , whatever be nature of charge 
(b) always decreases , whatever be nature of charge 
(c) always increases , whatever be nature of charge 
(d) a increase or decrease depending upon the nature of charge 

Answer : (b) 

23. Which of the following compounds will not undergo azo coupling reaction with benzene diazonium chloride ? 

(a) Aniline 
(b) Phenol 
(c) Anisole
(d) Nitrobenzene 

Answer : (d) 

24. If f(x) and | f(x) | are both differentiable , then f(x) is 

(a) left continuous at x = 0 
(b) right continuous at x= 0 
(c) not continuous at x= 0 
(d) continuous everywhere 

Answer : (d) 

25. Of the following 0.10 m aqueous solutions , which one will exhibit the largest freezing point depression ? 

(a) KCl 
(b) C6H12O6
(c) Al2(SO4)3 
(d) K2SO4 

Answer : (c) 

26. The area bounded by the curve y^2 = 9x and the lines x = 1 , x = 4 and y = 0 in the first quadrant is 

(a) 7
(b) 14
(c) 14/3
(d) 28 

Answer : (b) 

27. The intensity level of two sounds are 100 dB and 50 dB . What is the ratio of their intensities ? 

(a) 10^1 
(b) 10^3 
(c) 10^5 
(d) 10^10 

Answer : (c) 

28. At room temperature , the rms speed of the molecules of a certain diatomic gas is found to be 1930 m/s . The gas is 

(a) H2
(b) F2
(c) O2
(d) Cl2 

Answer : (a) 

29. The KE and PE of a particle executing SHM with amplitude A will be equal when its displacement is 

(a) A√2
(b) A/2
(c) A/√2
(d) A√(2/3) 

Answer : (a) 

30. The degree and order of the differential equation of the family of all parabola whose axis is x axis are respectively 

(a) 3,2
(b) 2,3
(c) 2,1
(d) 1,2 

Answer : (d) 

















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