1.When dilute HCl is added to zinc pieces taken in a test tube
(a)No change takes place
(b)the colour of the solution becomes yellow.
(c)A pungent smelling gas gets liberated.
(d)small bubbles of H2 gas appear on the surface of zinc pieces
 Ans. (d) Small bubbles of H2 gas Appear on the surface of zinc pieces.


2  .PbS reacts with ozone (O3) and forms pbso4. As per the balanced equation, molecules of ozone required for every one molecule of PbS is / are
(a)4
(b)3
 (c)2
(d)1
 Ans. (a) 4


3.In the reaction PbO + C Pb + CO
 (a)Pbo is oxidised
 (b)C act as an oxidising agent
(c)C act as a reduction agent
 (d)Reaction does not represent redox reaction.
 Ans. (c) C act as a reduction agent


4 .A substance which oxidizes itself and reduces other is known as (a)Oxidising agent
 (b)reducing agent
 (c)Both (a) and (b) (d)None of these.
Ans. (b) reducing agent


5.Take about 5 ml of dil. HCl in a test tube and add a few pieces of fine granules to it. Which gas is evolved?
 (a)Chlorine
(b)Hydrogen
(c)HCl
 (d)Nitrogen
 Ans. (b) Hydrogen


6.Dissolving suger is an example of
(a)Physical change
(b)Chemical change
(c)Redox Reaction
 (d)None of these.
Ans. (a) Physical change


7 .Way do diamond and graphite, the two allotropic forms of carbon evolve different amounts of heat on combustion?
Ans. Diamond and graphite are the two allotropes of carbon but they do not evolve same amount of heat on combustion because they differ in the arrangement of carbon atoms and also their shapes one different.


8 .What is the sole of oxidizing agent is a reaction?
Ans. The oxidizing agent supply the oxygen in a reaction or it removes the hydrogen.


 9  .What happens chemically when quick lime is added to water?
Ans. When quick lime is added to water calcium hydroxide (slaked lime) is formed with a
hissing sound and lot of heat is evolved during the reaction. The reaction involved is CaO (s) + H2O(Quick Lime) Ca (OH) 2 (s) + Heat (Shaked Lime)


10  .Why a combustion reaction an oxidation reaction?
Ans. Combustion reaction because it is always carried out in the presence of air or oxygen for e.g. CH4 (g) + 2O2 (g) Co2 (g) +2H2O (l)


11  .Why are food particle preferably packed in aluminum foil?
Ans. Aluminium foil do not corrode in atmosphere even if kept for a long time because a protective coating of aluminium oxide (Al2O3) is formed on the surface of the foil and stops any further reaction of the metal with air and water thus food particles do not get spoiled.


12  .What happens to lime water when Co2 gas is bubbled through it in excess?
Ans. When CO2 gas is bubbled through lime water in excess then initially it becomes milky but then its milkiness disappears.

                                              MID TERM EXAMINATION 2018 - 19
                                                                      CLASS: X
                                                   SUBJECT – MATHEMATICS
TIME: 3HRS.                                                                                                                            M.M. 80
General Instructions  :
 1. All questions are compulsory.
 2. The question paper consist of 30 questions divided into four sections A, B, C and D.
 3. Section A contains 6 questions 1 mark each question.
 4. Section B contains 6 questions 2 mark each question.
 5. Section C contains 10 questions 3 mark each question.
 6. Section D contains 8 questions 4 mark each question.
 7. There is no overall choice. However, an internal choice has been provided in 4 questions of 3               marks each and 3 questions of 4 marks each. You have to attempt only on the alternatives in all           such questions.
 8. Use of calculator is not permitted.

                                                                  SECTION – A

1. The decimal expansion of rational number 49/40 will terminate after how many places of decimal?  2. Check whether (x + 3)3 = x3 – 8 is a quadratic equation ?     
3. Find the next term of the A.P. √8, √18, √32,……. 
4. If ∆ABC ~ ∆DEF such that ∠A = 45 and ∠E = 56, then find the value of ∠C.         
5. The ordinate of a point A on the y-axis is 5 and B has coordinates (-3, 1), then find the length of AB. 
6. Two players, Rajiv and Raju play a badminton match. If the probability of Raju’s winning the match is 0.62, then find the probability of Rajiv’s winning.

                                                                      SECTION - B
 7. Show that any positive odd integer is of the for 4q + 1 or 4q + 3, where q is some positive       integer.   

 8. Find a quadratic polynomial, the sum and product of whose zeroes are 5 and -2 respectively.

 9.   The ladder is placed against a wall such that its foot is at distance of 5m from the wall and its top reaches a window 5√3m above the ground. Find the length of ladder. 


10. If the point (m,3) lies on the line segment joining the points
A(- 2 5 ,6) and B(2,8), find the value of m.       


11. The following table shows the cumulative frequency distribution of marks of 800 students in an examination. Marks No. of Students Marks No. of Students Below 10 Below 20 Below 30 Below 40 Below 50 10 50 130 270 440 Below 60 Below 70 Below 80 Below 90 Below 100 570 670 740 780 800 Construct a frequency distribution table for the above data.

12. A card is drawn at random from a well-shuffled deck of 52 playing cards. Find the probability of getting neither a red colour card nor a queen.       




                                                                    SECTION - C
  13. The traffic lights at three different road crossing change after every 48 seconds, 72 seconds and 108 seconds respectively. If they change simultaneously at 9:00 AM, at what time will they change simultaneously again ?     3

OR Find the HCF and LCM of 78, 52, 91 using the prime factorisation method.

14. Solve : 43x + 67y = -24 67 x + 43y = 24 

OR Draw the graph of 2x + y = 6 and 2x – y + 2 = 0/ Shade the region bounded by these lines and x-axis. Find the area of the shaded region.

15. The cost of 5 oranges and 3 apples is Rs 30 and the cost of 2 oranges and 4 apples is Rs 26. Find the cost of an orange and an apple.     

16. A two digit number is such that the product of its digit is 18. When 63 is subtracted from the numbers, the digits interchange their places. Find the number.

17.  If the sum of first n terms of an A.P. is given by Sn = 3n2 +5n, find the nth term of the A.P. 

OR If the sum of first 9 terms of an A.P. is 81 and that of first 17 terms is 289, find the sum of first n terms.


18. In figure, the line segment ST is parallel to side PR of ∆PQR and it divides the triangle into two parts of equal area. Find the ratio PS PQ .          3 * *
OR In the given figure, ABIIPQIICD, AB = x, CD = y and PQ = z, then prove that 1 x + 1 y = 1 z


19. Find the ratio in which the line x – y = 2 divides the line segment joining the points A(3,1) and B(8,9). 

20. If the median of the distribution given below is 28.5, find the values of x and y :       3 Class interval 0-10 10-20 20-30 30-40 40-50 50-60 Total Frequency 5 x 20 15 y 5 60

  21. Find the mean and mode age in years for the following frequency distribution :        3 Age (in years) 10-19 20-29 30-39 40-49 50-59 60-69 No. of persons 8 8 10 14 28 12

     22. Two coins are tosses simultaneously. Find the probability of getting :         3 (i)  Two heads (ii) No head

                                                                          SECTION – D

23. Prove that √5 is an irrational number.     4 



24. Find the values of a and b so that x4 + x3 + 8x2 +ax +b is divisible by x2 + 1.     


  25. Solve for x and y :       4
 44 x+y + 30 x−y = 10
 55 x+y + 40 x−y = 13 


26. If -5, 2x2 + px -15 = 0 and roots of p(x2 +x) + k = 0 are equal, then find the value of p and k.   OR Using quadratic formula, solve the following equation :  abx2 + (b2 – ac)x –bc = 0

27. Find the value of the middle term of the A.P. 7, 13, 19..., 247.

28. State and prove the Basic Proportionality Theorem.   4   29. Show that points (1,7), (4,2), (-1,-1) and (-4,4) are the vertices of a square.     



29. Show that points (1,7), (4,2), (-1,-1) and (-4,4) are the vertices of a square




30. Find the mean of the following distribution by step- deviation method :         4 Daily expenditure (in Rs) 100-150 150-200 200-250 250-300 300-350
No. of households 4 5 12 2 2     

1. In the reaction PbO + C Pb + CO 
(a) Pbo is oxidised 
(b) C act as an oxidising agent 
(c) C act as a reduction agent 
(d) Reaction does not represent redox reaction. 
Ans. (c) C act as a reduction agent