问题 选择题

关于溶液的酸碱性说法正确的是 (  )

A.c(H+)很小的溶液一定呈碱性

B.PH=7的溶液一定呈中性

C.不能使酚酞试液变红的溶液一定呈酸性

D.c(OH-)= C(H+)的溶液一定呈中性

答案

答案:D

题目分析:A.溶液的酸碱性取决于溶液中c(OH)、c(H+)的相对大小,如果c(OH)>c(H+),溶液呈碱性,如果c(OH)=c(H+),溶液呈中性,如果c(OH)<c(H+),溶液呈酸性,如果酸的浓度很小,则c(H+)很小,但溶液仍可能呈酸性,故A错误;B.pH=7的溶液不一定呈中性,如100℃时,纯水的pH<7,则该温度下,pH=7的溶液呈碱性,只有c(OH)=c(H+)时,溶液一定呈中性与PH无必然联系,故B错误;D.溶液中如果c(OH)=c(H+),则溶液呈中性,故D正确;C.酚酞的变色范围是8﹣10,所以能使酚酞试液变红的溶液呈碱性,不能使酚酞试液变红的溶液,可能是盐的中性溶液或酸性溶液,如氯化钠盐溶液不能使酚酞试液变红,故C错误;故选D。)、c(H+)的相对大小是解本题关键,题目难度不大。

完形填空
完形填空
     Although I love my life, it hasn't been a lot of fun as I've been ill for 28 years.
     Music has always been a great love of mine and, in my 20s, when my__1__ was more manageable,
I __2__ ten years as a professional singer in restaurants, playing and singing folk songs.__3__ that was
years ago and times have changed.__4__I live with my mother on a country farm.
     Two years ago, I decided that I would need to have some kind of extra work to__5__ my disability
pension (残疾抚恤金). __6__ I needed to sleep in the afternoons, I was limited in my __7__.I decided
that I would consider __8__to singing in restaurants.
     My family are all musicians, so I was__9__ when I went into our local music store.I explained that I
wanted to sing again but using recorded karaoke music.I knew that discs were very expensive and I really didn't have a lot of __10__ to get started.And__11__ you find only three to four songs out of ten on a
disc that you can __12__use.
     When I told the owner of the shop about my __13__, he gave me a long, thoughtful __14__."This
means a lot to you, doesn't it?" he said."Come with me."
     He led me __15__the crowded shop and to a bench with a large professional karaoke box on it.He
placed his large hand __16__ on his treasure and said, "I have 800 karaoke songs in here.You can take
your __17__and I'll record them for you.That should get you started."
     I __18__.Thanking him, I made a time with him to listen to all the songs and choose__19__ that I
could sing.I have come full circle with his help.
     His __20__ still warms my heart and makes me do just that bit extra, when I have the chance.
( )1. A. loneliness    
( )2. A. set          
( )3. A. Gladly        
( )4. A. Now          
( )5. A. add up to    
( )6. A. If            
( )7. A. movement      
( )8. A. reaching out  
( )9. A. recognized    
( )10. A. money        
( )11. A. thus        
( )12. A. actually    
( )13. A. job          
( )14. A. face        
( )15. A. over        
( )16. A. unhappily    
( )17. A. pick        
( )18. A. had to cry  
( )19. A. more        
( )20. A. courage      
B. sadness        
B. enjoyed        
B. Eventually      
B. Then            
B. make up for    
B. As              
B. condition      
B. living up      
B. interviewed    
B. time            
B. once            
B. hardly          
B. family          
B. view            
B. along          
B. lovingly        
B. turn            
B. ought to cry    
B. the ones        
B. devotion        
C. tiredness          
C. kept              
C. Unfortunately      
C. Sometime          
C. get rid of        
C. Though            
C. choices            
C. getting on        
C. found              
C. energy            
C. seldom            
C. nearly            
C. idea              
C. look              
C. towards            
C. pitifully          
C. role              
C. should have cried  
C. few                
C. kindness          
D. sickness            
D. shared              
D. Surprisingly        
D. Meanwhile            
D. take advantage of    
D. Before              
D. positions            
D. going back          
D. invited              
D. knowledge            
D. often                
D. formerly            
D. offer                
D. sight                
D. through              
D. gratefully          
D. step                
D. could have cried    
D. the rest            
D. trust                
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